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OWNER’S SERVICE MANUAL
MANUEL D’ATELIER DU
PROPRIETAIRE
FAHRER- UND
WARTUNGSHANDBUCH
MANUALE DI SERVIZIO DEL
PROPRIETARI
O
YZ125
(
D
)
1SR-28199-31
PRINTED IN JAPAN
2012.08—0.8 × 1
!
(E, F, G, H)
PRINTED ON RECYCLED PAPER
2013
YZ125
(
D
)
2013
q Read this manual carefully before operating this vehicle.
q Il convient de lire attentivement ce manuel avant la première utilisation du véhicule.
q
Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch, bevor Sie das Fahrzeug in Betrieb nehmen.
q Leggere attentamente questo manuale prima di utilizzare questo veicolo.
1SR-9-31_cover.indd 1 2012/09/15 15:56:32
Q
Read this manual carefully before operating this vehicle. This manual should stay with this vehicle if it is sold.
Q
Il convient de lire attentivement ce manuel avant la première utilisation du véhicule. Le manuel doit
être remis avec le véhicule en cas de vente de ce dernier.
Q
Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch, bevor Sie das Fahrzeug in Betrieb nehmen.
Diese Bedienungsanleitung muss, wenn das Fahrzeug verkauft wird, beim Fahrzeug verbleiben.
Q
Leggere attentamente questo manuale prima di utilizzare il veicolo. Questo manuale dovrebbe
accompagnare il veicolo se viene venduto.
1P8-9-36_cover 10.6.16 9:57 ページ 2
YZ125(D)YZ125(D)
20132013
1SR-28199-31-E01SR-28199-31-E0
OWNER’S SERVICE MANUALOWNER’S SERVICE MANUAL
Read this manual carefully before operating this vehicle.Read this manual carefully before operating this vehicle.
YZ125 (D)
OWNER'S SERVICE MANUAL
©2012 by Yamaha Motor Co., Ltd.
1st Edition, September 2012
All rights reserved.Any reprinting or
unauthorized use without the written
permission of Yamaha Motor Co., Ltd.
is expressly prohibited.
Printed in Japan
FOREWORD
INTRODUCTION
Congratulations on your purchase of
a Yamaha YZ series. This model is
the culmination of Yamaha's vast ex-
perience in the production of paceset-
ting racing machines. It represents
the highest grade of craftsmanship
and reliability that have made Yama-
ha a leader.
This manual explains operation, in-
spection, basic maintenance and tun-
ing of your machine. If you have any
questions about this manual or your
machine, please contact your Yama-
ha dealer.
Yamaha continually seeks advance-
ments in product design and quality.
Therefore, while this manual contains
the most current product information
available at the time of printing, there
may be minor discrepancies between
your machine and this manual. If you
have any questions concerning this
manual, please consult your Yamaha
dealer.
PLEASE READ THIS MANUAL
CAREFULLY AND COMPLETELY
BEFORE OPERATING THIS MA-
CHINE. DO NOT ATTEMPT TO OP-
ERATE THIS MACHINE UNTIL YOU
HAVE ATTAINED A SATISFACTO-
RY KNOWLEDGE OF ITS CON-
TROLS AND OPERATING
FEATURES AND UNTIL YOU HAVE
BEEN TRAINED IN SAFE AND
PROPER RIDING TECHNIQUES.
REGULAR INSPECTIONS AND
CAREFUL MAINTENANCE,
ALONG WITH GOOD RIDING
SKILLS, WILL ENSURE THAT YOU
SAFETY ENJOY THE CAPABILI-
TIES AND THE RELIABILITY OF
THIS MACHINE.
IMPORTANT MANUAL
INFORMATION
Particularly important information is
distinguished in this manual by the
following notations.
This is the safety alert symbol. It is
used to alert you to potential per-
sonal injury hazards. Obey all safe-
ty messages that follow this
symbol to avoid possible injury or
death.
A WARNING indicates a hazardous
situation which, if not avoided,
could result in death or serious in-
jury.
A NOTICE indicates special pre-
cautions that must be taken to
avoid damage to the vehicle or oth-
er property.
A TIP provides key information to
make procedures easier or clearer.
SAFETY INFORMATION
THIS MACHINE IS DESIGNED
STRICTLY FOR COMPETITION
USE, ONLY ON A CLOSED
COURSE. It is illegal for this machine
to be operated on any public street,
road, or highway. Off-road use on
public lands may also be illegal.
Please check local regulations before
riding.
THIS MACHINE IS TO BE OPER-
ATED BY AN EXPERIENCED RID-
ER ONLY.
Do not attempt to operate this ma-
chine at maximum power until you
are totally familiar with its character-
istics.
THIS MACHINE IS DESIGNED TO
BE RIDDEN BY THE OPERATOR
ONLY.
Do not carry passengers on this
machine.
ALWAYS WEAR PROTECTIVE
APPAREL.
When operating this machine, al-
ways wear an approved helmet with
goggles or a face shield. Also wear
heavy boots, gloves, and protective
clothing. Always wear proper fitting
clothing that will not be caught in
any of the moving parts or controls
of the machine.
ALWAYS MAINTAIN YOUR MA-
CHINE IN PROPER WORKING
ORDER.
For safety and reliability, the ma-
chine must be properly maintained.
Always perform the pre-operation
checks indicated in this manual.
Correcting a mechanical problem
before you ride may prevent an ac-
cident.
GASOLINE IS HIGHLY FLAMMA-
BLE.
Always turn off the engine while re-
fueling. Take care to not spill any
gasoline on the engine or exhaust
system. Never refuel in the vicinity
of an open flame, or while smoking.
GASOLINE CAN CAUSE INJURY.
If you should swallow some gaso-
line, inhale excess gasoline vapors,
or allow any gasoline to get into
your eyes, contact a doctor immedi-
ately. If any gasoline spills onto
your skin or clothing, immediately
wash skin areas with soap and wa-
ter, and change your clothes.
ONLY OPERATE THE MACHINE
IN AN AREA WITH ADEQUATE
VENTILATION.
Never start the engine or let it run
for any length of time in an enclosed
area. Exhaust fumes are poison-
ous. These fumes contain carbon
monoxide, which by itself is odor-
less and colorless. Carbon monox-
ide is a dangerous gas which can
cause unconsciousness or can be
lethal.
PARK THE MACHINE CAREFUL-
LY; TURN OFF THE ENGINE.
Always turn off the engine if you are
going to leave the machine. Do not
park the machine on a slope or soft
ground as it may fall over.
THE ENGINE, EXHAUST PIPE,
MUFFLER, AND OIL TANK WILL
BE VERY HOT AFTER THE EN-
GINE HAS BEEN RUN.
Be careful not to touch them or to
allow any clothing item to contact
them during inspection or repair.
PROPERLY SECURE THE MA-
CHINE BEFORE TRANSPORTING
IT.
When transporting the machine in
another vehicle, always be sure it is
properly secured and in an upright
position and that the fuel cock is in
the "OFF" position. Otherwise, fuel
may leak out of the carburetor or
fuel tank.
HOW TO USE THIS MANUAL
FINDING THE REQUIRED PAGE
1. This manual consists of seven
chapters; "General Information",
"Specifications", "Regular inspec-
tion and adjustments", "Engine",
"Chassis", "Electrical" and "Tun-
ing"
2. The table of contents is at the be-
ginning of the manual. Look over
the general layout of the book be-
fore finding then required chapter
and item.
Bend the book at its edge, as
shown, to find the required fore
edge symbol mark and go to a
page for required item and de-
scription.
MANUAL FORMAT
All of the procedures in this manual
are organized in a sequential, step-
by-step format. The information has
been complied to provide the me-
chanic with an easy to read, handy
reference that contains comprehen-
sive explanations of all disassembly,
repair, assembly, and inspection op-
erations.
In this revised format, the condition of
a faulty component will precede an
arrow symbol and the course of ac-
tion required will follow the symbol,
e.g.,
Bearings
Pitting/damage Replace.
HOW TO READ DESCRIPTIONS
To help identify parts and clarify pro-
cedure steps, there are exploded dia-
grams at the start of each removal
and disassembly section.
1. An easy-to-see exploded diagram
"1" is provided for removal and
disassembly jobs.
2. Numbers "2" are given in the or-
der of the jobs in the exploded di-
agram. A number that is enclosed
by a circle indicates a disassem-
bly step.
3. An explanation of jobs and notes
is presented in an easy-to-read
way by the use of symbol marks
"3". The meanings of the symbol
marks are given on the next page.
4. A job instruction chart "4" accom-
panies the exploded diagram,
providing the order of jobs, names
of parts, notes in jobs, etc.
5. For jobs requiring more informa-
tion, the step-by-step format sup-
plements "5" are given in addition
to the exploded diagram and job
instruction chart.
ILLUSTRATED SYMBOLS (Refer to
the illustration)
Illustrated symbols "1" to "7" are used
to identify the specifications appear-
ing in the text.
1. With engine mounted
2. Filling fluid
3. Lubricant
4. Special tool
5. Tightening
6. Specified value, Service limit
7. Resistance (Ω), Voltage (V),
Electric current (A)
Illustrated symbols "8" to "14" in the
exploded diagrams indicate grade of
lubricant and location of lubrication
point.
8. Apply engine mixing oil
9. Apply transmission oil
10. Apply molybdenum disulfide oil
11. Apply brake fluid
12. Apply lightweight lithium-soap
base grease
13. Apply molybdenum disulfide
grease
14. Apply silicone grease
Illustrated symbols "15" to "16" in the
exploded diagrams indicate where to
apply a locking agent and where to in-
stall new parts.
15. Apply locking agent (LOC-
TITE
®
)
16. Use new one
1
2
3
4
5
TABLE OF CONTENTS
GENERAL INFORMATION
1
SPECIFICATIONS
2
REGULAR INSPECTION AND
ADJUSTMENTS
3
ENGINE
4
CHASSIS
5
ELECTRICAL
6
TUNING
7
CONTENTS
CHAPTER 1
GENERAL
INFORMATION
LOCATION OF IMPORTANT
LABELS............................ 1-1
DESCRIPTION ................. 1-5
CONSUMER
INFORMATION................. 1-6
INCLUDED PARTS .......... 1-6
IMPORTANT
INFORMATION................. 1-6
CHECKING OF
CONNECTION.................. 1-7
SPECIAL TOOLS ............. 1-8
CONTROL
FUNCTIONS ................... 1-11
STARTING AND
BREAK-IN ...................... 1-12
TORQUE-CHECK
POINTS........................... 1-13
CLEANING AND
STORAGE ...................... 1-14
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS............ 2-1
MAINTENANCE
SPECIFICATIONS............ 2-2
TIGHTENING TORQUES . 2-7
CABLE ROUTING
DIAGRAM....................... 2-13
CHAPTER 3
REGULAR INSPEC-
TION AND AD-
JUSTMENTS
MAINTENANCE
INTERVALS......................3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................3-5
ENGINE ............................3-6
CHASSIS ..........................3-9
ELECTRICAL .................3-19
CHAPTER 4
ENGINE
SEAT, FUEL TANK AND
SIDE COVERS.................. 4-1
EXHAUST PIPE AND
SILENCER ........................4-3
RADIATOR ....................... 4-5
CARBURETOR AND
REED VALVE ................... 4-7
CYLINDER HEAD, CYLIN-
DER AND PISTON .........4-12
CLUTCH .........................4-19
KICK SHAFT AND
SHIFT SHAFT.................4-23
YPVS GOVERNOR......... 4-28
WATER PUMP................4-30
CDI MAGNETO............... 4-33
ENGINE REMOVAL ....... 4-35
CRANKCASE AND
CRANKSHAFT ............... 4-39
TRANSMISSION, SHIFT
CAM AND SHIFT FORK.4-44
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR
WHEEL .............................5-1
FRONT BRAKE AND
REAR BRAKE ..................5-6
FRONT FORK.................5-16
HANDLEBAR..................5-24
STEERING ......................5-29
SWINGARM ....................5-33
REAR SHOCK
ABSORBER....................5-38
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPO-
NENTS AND WIRING DIA-
GRAM ...............................6-2
IGNITION SYSTEM...........6-3
CHAPTER 7
TUNING
ENGINE.............................7-1
CHASSIS ..........................7-6
1-1
LOCATION OF IMPORTANT LABELS
GENERAL INFORMATION
LOCATION OF IMPORTANT LABELS
Please read the following important labels carefully before operating this vehicle.
CANADA
1
1-2
LOCATION OF IMPORTANT LABELS
1-3
LOCATION OF IMPORTANT LABELS
EUROPE
AUS, NZ, ZA
1-4
LOCATION OF IMPORTANT LABELS
Familiarize yourself with the following pictograms and read the explanatory text.
Read Owner's service manual.
This unit contains high-pressure nitrogen gas. Mishandling can cause explosion. Do not incinerate,
puncture or open.
Turn off the main switch after riding to avoid draining the battery.
Use unleaded gasoline only.
Measure tire pressure when tires are cold.
Adjust tire pressure.
Improper tire pressure can cause loss of control.
Loss of control can result in severe injury or death.
1-5
DESCRIPTION
DESCRIPTION
The machine you have purchased may differ slightly from those shown in the following.
Designs and specifications are subject to change without notice.
1. Clutch lever
2. Engine stop switch
3. Front brake lever
4. Throttle grip
5. Radiator cap
6. Fuel tank cap
7. Kickstarter crank
8. Fuel tank
9. Radiator
10. Coolant drain bolt
11. Check bolt (Transmission oil level)
12. Rear brake pedal
13. Valve joint
14. Fuel cock
15. Air filter
16. Drive chain
17. Shift pedal
18. Starter knob
19. Front fork
1-6
CONSUMER INFORMATION
CONSUMER INFORMATION
There are two significant reasons for
knowing the serial number of your
machine:
1. When ordering parts, you can
give the number to your Yamaha
dealer for positive identification of
the model you own.
2. If your machine is stolen, the au-
thorities will need the number to
search for and identify your ma-
chine.
VEHICLE IDENTIFICATION
NUMBER
The vehicle identification number "1"
is stamped on the right of the steering
head pipe.
ENGINE SERIAL NUMBER
The engine serial number "1" is
stamped into the elevated part of the
right-side of the engine.
MODEL LABEL
The model label "1" is affixed to the
frame under the rider's seat. This in-
formation will be needed to order
spare parts.
INCLUDED PARTS
DETACHABLE SIDESTAND
This sidestand "1" is used to support
only the machine when standing or
transporting it.
Never apply additional force to
the sidestand.
Remove this sidestand before
starting out.
VALVE JOINT
This valve joint "1" prevents fuel from
flowing out and is installed to the fuel
tank breather hose.
In this installation, make sure the
arrow faces the fuel tank and also
downward.
COLLAR (tool for YPVS)
This collar "1" is used to remove and
install the push rod of the engine.
NIPPLE WRENCH
This nipple wrench "1" is used to
tighten the spoke.
IMPORTANT INFORMATION
PREPARATION FOR REMOVAL
AND DISASSEMBLY
1. Remove all dirt, mud, dust, and
foreign material before removal
and disassembly.
When washing the machine with
high pressured water, cover the
parts follows.
Silencer exhaust port
Side cover air intake port
Crankcase cover hole at the bot-
tom
Water pump housing hole at the
bottom
End of each hose
2. Use proper tools and cleaning
equipment. Refer to "SPECIAL
TOOLS" section.
3. When disassembling the ma-
chine, keep mated parts together.
They include gears, cylinders,
pistons, and other mated parts
that have been "mated" through
normal wear. Mated parts must
be reused as an assembly or re-
placed.
1-7
CHECKING OF CONNECTION
4. During the machine disassembly,
clean all parts and place them in
trays in the order of disassembly.
This will speed up assembly time
and help assure that all parts are
correctly reinstalled.
5. Keep away from fire.
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha
genuine parts for all replace-
ments. Use oil and/or grease rec-
ommended by Yamaha for
assembly and adjustment.
GASKETS, OIL SEALS AND O-
RINGS
1. All gaskets, oil seals, and O-rings
should be replaced when an en-
gine is overhauled. All gasket sur-
faces, oil seal lips, and O-rings
must be cleaned.
2. Properly oil all mating parts and
bearings during reassembly. Ap-
ply grease to the oil seal lips.
LOCK WASHERS/PLATES AND
COTTER PINS
1. All lock washers/plates "1" and
cotter pins must be replaced
when they are removed. Lock
tab(s) should be bent along the
bolt or nut flat(s) after the bolt or
nut has been properly tightened.
BEARINGS AND OIL SEALS
1. Install the bearing(s) "1" and oil
seal(s) "2" with their manufactur-
er's marks or numbers facing out-
ward. (In other words, the
stamped letters must be on the
side exposed to view.) When in-
stalling oil seal(s), apply a light
coating of lightweight lithium base
grease to the seal lip(s). Oil the
bearings liberally when installing.
Do not use compressed air to spin
the bearings dry. This causes dam-
age to the bearing surfaces.
CIRCLIPS
1. All circlips should be inspected
carefully before reassembly. Al-
ways replace piston pin clips after
one use. Replace distorted cir-
clips. When installing a circlip "1",
make sure that the sharp-edged
corner "2" is positioned opposite
to the thrust "3" it receives. See
the sectional view.
CHECKING OF
CONNECTION
Dealing with stains, rust, moisture,
etc. on the connector.
1. Disconnect:
Connector
2. Dry each terminal with an air
blower.
3. Connect and disconnect the con-
nector two or three times.
4. Pull the lead to check that it will
not come off.
5. If the terminal comes off, bend up
the pin "1" and reinsert the termi-
nal into the connector.
6. Connect:
Connector
The two connectors "click" together.
7. Check for continuity with a tester.
If there in no continuity, clean the
terminals.
Be sure to perform the steps 1 to 7
listed above when checking the
wire harness.
For a field remedy, use a contact re-
vitalizer available on the market.
Use the tester on the connector as
shown.
1-8
SPECIAL TOOLS
SPECIAL TOOLS
The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will
help prevent damage caused by the use of improper tools or improvised techniques. The shape and part number used for
the special tool differ by country, so two types are provided. Refer to the list provided to avoid errors when placing an order.
For U.S.A. and Canada, use part number starting with "YM-", "YU-" or "ACC-".
For others, use part number starting with "90890-".
Tool name/Part number How to use Illustration
Crankcase separating tool
YU-1135-A, 90890-01135
These tool is used to remove the
crankshaft from either case.
Flywheel puller
YM-1189, 90890-01189
This tool is used to remove the fly-
wheel magneto.
Rotor holding tool
YU-1235, 90890-01235
This tool is used when loosening or
tightening the flywheel magneto se-
curing nut.
Dial gauge and stand
YU-3097, 90890-01252
Stand
YU-1256
These tools are used to check each
part for runout or bent.
Crankshaft installing tool
Crankshaft installing pot
YU-90050, 90890-01274
Crankshaft installing bolt
YU-90050, 90890-01275
Adapter
YU-90063, 90890-01278
Adapter
YU-01499, 90890-01499
These tools are used to install the
crankshaft.
Piston pin puller set
YU-1304, 90890-01304
This tool is used to remove the pis-
ton pin.
1-9
SPECIAL TOOLS
Fuel level gauge "1"
YM-1312-A, 90890-01312
Fuel level gauge adaptor "2"
YM-01470, 90890-01470
This gauge is used to measure the
fuel level in the float chamber.
Radiator cap tester
YU-24460-01, 90890-01325
Radiator cap tester adapter
YU-33984, 90890-01352
These tools are used for checking
the cooling system.
Flywheel puller
YU-33270-B, 90890-01362
These tool is used to split the crank-
case.
Steering nut wrench
YU-33975, 90890-01403
This tool is used when tighten the
steering ring nut to specification.
Cap bolt wrench
YM-01500, 90890-01500
This tool is used to loosen or tighten
the base valve.
Cap bolt ring wrench
YM-01501, 90890-01501
This tool is used to loosen or tighten
the damper assembly.
Tool name/Part number How to use Illustration
1-10
SPECIAL TOOLS
Fork seal driver
YM-A0948, 90890-01502
This tool is used when install the fork
oil seal.
Spoke nipple wrench
YM-01521, 90890-01521
This tool is used to tighten the
spoke.
Pocket tester
YU-3112-C, 90890-03112
Use this tool to inspect the coil resis-
tance, output voltage and amper-
age.
Clutch holding tool
YM-91042, 90890-04086
This tool is used to hold the clutch
when removing or installing the
clutch boss securing nut.
Dynamic spark tester
YM-34487
Ignition checker
90890-06754
This instrument is necessary for
checking the ignition system compo-
nents.
Yamaha Bond No. 1215 (Three-
Bond
®
No. 1215)
90890-85505
This sealant (Bond) is used for
crankcase mating surface, etc.
Tool name/Part number How to use Illustration
1-11
CONTROL FUNCTIONS
CONTROL FUNCTIONS
ENGINE STOP SWITCH
The engine stop switch "1" is located
on the left handlebar. Continue push-
ing the engine stop switch till the en-
gine comes to a stop.
CLUTCH LEVER
The clutch lever "1" is located on the
left handlebar; it disengages or en-
gages the clutch. Pull the clutch lever
to the handlebar to disengage the
clutch, and release the lever to en-
gage the clutch. The lever should be
pulled rapidly and released slowly for
smooth starts.
SHIFT PEDAL
The gear ratios of the constant-mesh
6 speed transmission are ideally
spaced. The gears can be shifted by
using the shift pedal "1" on the left
side of the engine.
KICKSTARTER CRANK
Rotate the kickstarter crank "1" away
from the engine. Push the starter
down lightly with your foot until the
gears engage, then kick smoothly
and forcefully to start the engine. This
model has a primary kickstarter crank
so the engine can be started in any
gear if the clutch is disengaged. In
normal practices, however, shift to
neutral before starting.
THROTTLE GRIP
The throttle grip "1" is located on the
right handlebar; it accelerates or de-
celerates the engine. For accelera-
tion, turn the grip toward you; for
deceleration, turn it away from you.
FRONT BRAKE LEVER
The front brake lever "1" is located on
the right handlebar. Pull it toward the
handlebar to activate the front brake.
REAR BRAKE PEDAL
The rear brake pedal "1" is located on
the right side of the machine. Press
down on the brake pedal to activate
the rear brake.
FUEL COCK
The fuel cock supplies fuel from the
tank to carburetor and also filters the
fuel. The fuel cock has the two posi-
tions:
OFF:
With the lever in this position, fuel will
not flow. Always return the lever to
this position when the engine is not
running.
ON:
With the lever in this position, fuel
flows to the carburetor. Normal riding
is done with the lever in this position.
STARTER KNOB (CHOKE)
When cold, the engine requires a
richer air-fuel mixture for starting. A
separate starter circuit, which is con-
trolled by the starter knob "1", sup-
plies this mixture. Pull the starter
knob out to open the circuit for start-
ing. When the engine has warmed
up, push it in to close the circuit.
1-12
STARTING AND BREAK-IN
STARTING AND BREAK-IN
FUEL
Mix oil with the gas at the ratio speci-
fied below. Always use fresh, name-
brand gasoline, and mix the oil and
gas the day of the race. Do not use
premix that is more than a few hours
old.
If knocking or pinging occurs, use a
different brand of gasoline or higher
octane grade.
Never mix two types of oil in the
same batch; clotting of the oil
could result. If you wish to change
oil types, be sure to drain the fuel
tank and the carburetor float bowl
of old premix prior to filling with
the new type.
HANDLING NOTE
Before starting the machine, per-
form the checks in the pre-opera-
tion check list.
Never start or run the engine in a
closed area. The exhaust fumes
are poisonous; they can cause
loss of consciousness and death
in a very short time. Always oper-
ate the machine in a well-ventilated
area.
AIR FILTER MAINTENANCE
According to "CLEANING THE AIR
FILTER ELEMENT" section in the
CHAPTER 3, apply the foam-air-filter
oil or its equivalent to the element.
(Excess oil in the element may ad-
versely affect engine starting.)
STARTING A COLD ENGINE
1. Shift the transmission into neutral.
2. Turn the fuel cock to "ON" and full
open the starter knob (CHOKE).
3. With the throttle completely
closed start the engine by kicking
the kick starter forcefully with firm
stroke.
4. Run the engine at idle or slightly
higher until it warms up: this usu-
ally takes about one or two min-
utes.
5. The engine is warmed up when it
responds normally to the throttle
with the starter knob (CHOKE)
turned off.
Do not warm up the engine for ex-
tended periods of time.
STARTING A WARM ENGINE
Do not operate the starter knob
(CHOKE). Open the throttle slightly
and start the engine by kicking the
kick starter forcefully with firm stroke.
Observe the following break-in
procedures during initial operation
to ensure optimum performance
and avoid engine damage.
BREAK-IN PROCEDURES
1. Before starting the engine, fill the
fuel tank with a break-in oil-fuel
mixture as follows.
2. Perform the pre-operation checks
on the machine.
3. Start and warm up the engine.
Check the idle speed, and check
the operation of the controls and
the "ENGINE STOP" button.
4. Operate the machine in the lower
gears at moderate throttle open-
ings for five to eight minutes. Stop
and check the spark plug condi-
tion; it will show a rich condition
during break-in.
5. Allow the engine to cool. Restart
the engine and operate the ma-
chine as in the step above for five
minutes. Then, very briefly shift to
the higher gears and check full-
throttle response. Stop and check
the spark plug.
6. After again allowing the engine to
cool, restart and run the machine
for five more minutes. Full throttle
and the higher gears may be
used, but sustained full-throttle
operation should be avoided.
Check the spark plug condition.
7. Allow the engine to cool, remove
the top end, and inspect the pis-
ton and cylinder. Remove any
high spots on the piston with #600
grit wet sandpaper. Clean all
components and carefully reas-
semble the top end.
8. Drain the break-in oil-fuel mixture
from the fuel tank and refill with
the specified mix.
9. Restart the engine and check the
operation of the machine through-
out its entire operating range.
Stop and check the spark plug
condition. Restart the machine
and operate it for about 10 to 15
more minutes. The machine will
now be ready to race.
After the break-in or before each
race, you must check the entire
machine for loose fittings and
fasteners as per "TORQUE-
CHECK POINTS". Tighten all
such fasteners as required.
When any of the following parts
have been replaced, they must
be broken in.
CYLINDER AND CRANKSHAFT:
About one hour of break-in oper-
ation is necessary.
PISTON, RING AND GEARS:
These parts require about 30
minutes of break-in operation at
half-throttle or less. Observe the
condition of the engine carefully
during operation.
Recommended fuel:
Premium unleaded
gasoline only with a re-
search octane number
of 95 or higher.
Fuel tank capacity:
8.0 L (1.76 Imp gal, 2.11
US gal)
Mixing oil:
Recommended oil:
YAMALUBE "2-R"
(YAMALUBE racing 2-
cycle oil)
Mixing ratio: 30:1
If unavailable, use an
equivalent type of oil.
Mixing oil:
YAMALUBE "2-R"
Mixing ratio:
15:1
1-13
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
Concerning the tightening torque, refer to "TIGHTENING TORQUES" section in the CHAPTER 2.
Frame construction Frame to rear frame
Combined seat and fuel tank Fuel tank to frame
Exhaust system Silencer to rear frame
Engine mounting Frame to engine
Engine bracket to engine
Engine bracket to frame
Steering Steering stem to handlebar Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Suspension Front Steering stem to front fork Front fork to upper bracket
Front fork to lower bracket
Rear For link type Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Installation of rear shock absorber Rear shock absorber to frame
Installation of swingarm Tightening of pivot shaft
Wheel Installation of wheel Front Tightening of wheel axle
Tightening of axle holder
Rear Tightening of wheel axle
Wheel to rear wheel sprocket
Brake Front Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handlebar
Tightening of bleed screw
Tightening of brake hose holder
Rear Brake pedal to frame
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Tightening of brake hose holder
Fuel system Fuel tank to fuel cock
1-14
CLEANING AND STORAGE
CLEANING AND STORAGE
CLEANING
Frequent cleaning of your machine
will enhance its appearance, maintain
good overall performance, and ex-
tend the life of many components.
1. Before washing the machine,
block off the end of the exhaust
pipe to prevent water from enter-
ing. A plastic bag secured with a
rubber band may be used for this
purpose.
2. If the engine is excessively
greasy, apply some degreaser to
it with a paint brush. Do not apply
degreaser to the chain, sprockets,
or wheel axles.
3. Rinse the dirt and degreaser off
with a garden hose; use only
enough pressure to do the job.
Do not use high-pressure washers
or steam-jet cleaners since they
cause water seepage and deterio-
ration seals.
4. After the majority of the dirt has
been hosed off, wash all surfaces
with warm water and a mild deter-
gent. Use an old toothbrush to
clean hard-to-reach places.
5. Rinse the machine off immediate-
ly with clean water, and dry all
surfaces with a soft towel or cloth.
6. Immediately after washing, re-
move excess water from the
chain with a paper towel and lubri-
cate the chain to prevent rust.
7. Clean the seat with a vinyl uphol-
stery cleaner to keep the cover
pliable and glossy.
8. Automotive wax may be applied
to all painted or chromed surfac-
es. Avoid combination cleaner-
waxes, as they may contain abra-
sives.
9. After completing the above, start
the engine and allow it to idle for
several minutes.
STORAGE
If your machine is to be stored for 60
days or more, some preventive mea-
sures must be taken to avoid deterio-
ration. After cleaning the machine
thoroughly, prepare it for storage as
follows:
1. Drain the fuel tank, fuel lines, and
the carburetor float bowl.
2. Remove the spark plug, pour a ta-
blespoon of SAE 10W-40 motor
oil in the spark plug hole, and re-
install the plug. With the engine
stop switch pushed in, kick the en-
gine over several times to coat the
cylinder walls with oil.
3. Remove the drive chain, clean it
thoroughly with solvent, and lubri-
cate it. Reinstall the chain or store
it in a plastic bag tied to the frame.
4. Lubricate all control cables.
5. Block the frame up to raise the
wheels off the ground.
6. Tie a plastic bag over the exhaust
pipe outlet to prevent moisture
from entering.
7. If the machine is to be stored in a
humid or salt-air environment,
coat all exposed metal surfaces
with a film of light oil. Do not apply
oil to rubber parts or the seat cov-
er.
Make any necessary repairs before
the machine is stored.
2-1
GENERAL SPECIFICATIONS
SPECIFICATIONS
GENERAL SPECIFICATIONS
Model name: YZ125D (USA, CDN, AUS, NZ)
YZ125 (EUROPE, ZA)
Model code number: 1SR5 (USA, CDN)
1SR6 (EUROPE)
1SR8 (AUS, NZ, ZA)
Dimensions: USA, AUS, NZ, ZA EUROPE, CDN
Overall length 2,135 mm (84.1 in) 2,139 mm (84.2 in)
Overall width 827 mm (32.6 in)
Overall height 1,315 mm (51.8 in) 1,318 mm (51.9 in)
Seat height 997 mm (39.3in) 998 mm (39.3 in)
Wheelbase 1,443 mm (56.8 in)
Minimum ground clearance 386 mm (15.2 in) 388 mm (15.3 in)
Weight:
Curb weight 94 kg (207 lb)
Engine:
Engine type Liquid cooled 2-stroke, gasoline
Cylinder arrangement Single cylinder
Displacement 124 cm
3
(4.36 Imp oz, 4.19 US oz)
Bore × stroke 54 × 54.5 mm (2.1 × 2.1 in)
Compression ratio 8.6–10.7 : 1
Starting system Kick starter
Lubrication system: Premix (30 : 1)(YAMALUBE 2-R)
Oil type or grade (2-stroke):
Transmission oil Recommended brand: YAMALUBE
SAE10W-40
API service SG type or higher
JASO standard MA
Periodic oil change 0.66 L (0.58 Imp qt, 0.69 US qt)
Total amount 0.70 L (0.62 Imp qt, 0.74 US qt)
Coolant capacity (including all routes): 0.9 L (0.79 Imp qt, 0.95 US qt)
Air filter: Wet type element
Fuel:
Type Premium unleaded gasoline only with a research octane
number of 95 or higher.
Tank capacity 8.0 L (1.76 Imp gal, 2.11 US gal)
Carburetor:
Type/Manufacturer TMXχ38SS/MIKUNI
Spark plug:
Type/Manufacturer BR9EVX/NGK (resistance type)
Gap 0.6–0.7 mm (0.024–0.028 in)
Clutch type: Wet, multiple-disc
2
2-2
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINE
Transmission:
Primary reduction system Gear
Primary reduction ratio 3.368 (64/19)
Final drive Chain
Secondary reduction ratio 3.692 (48/13)
Transmission type Constant mesh, 6-speed
Operation Left foot operation
Gear ratio:
1st 2.385 (31/13)
2nd 1.933 (29/15)
3rd 1.588 (27/17)
4th 1.353 (23/17)
5th 1.200 (24/20)
6th 1.095 (23/21)
Chassis: USA, AUS, ZA, NZ EUROPE, CDN
Frame type Semi double cradle
Caster angle 25.50 ° 25.60 °
Trail 105 mm (4.1 in) 107 mm (4.2 in)
Tire:
Type With tube
Size (front) 80/100-21 51M
Size (rear) 100/90-19 57M
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2
, 15 psi)
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI magneto
Item Standard Limit
Cylinder head:
Combustion chamber volume 8.4 cm
3
(0.296 Imp oz, 0.284 US oz) ----
Warp limit ---- 0.03 mm
(0.0012 in)
2-3
MAINTENANCE SPECIFICATIONS
Cylinder:
Bore size 54.000–54.014 mm (2.1260–2.1265 in) 54.1 mm
(2.130 in)
Taper limit ---- 0.05 mm
(0.0020 in)
Out of round limit ---- 0.01 mm
(0.0004 in)
Piston:
Piston size/ 53.957–53.972 mm (2.1243–2.1249 in) ----
Measuring point "H" 17.5 mm (0.69 in) ----
Piston clearance 0.040–0.045 mmm (0.0016–0.0018 in) 0.1 mm (0.004
in)
Piston offset 0.5 mm (0.019 in)/EX-side ----
Piston pin:
Piston pin outside diameter 14.995–15.000 mm (0.5904–0.5906 in) 14.975 mm
(0.5896 in)
Piston ring:
Sectional sketch Plain ----
B=1.0 mm (0.039 in) ----
T=2.35 mm (0.093 in) ----
End gap (installed) 0.5–0.7 mm (0.020–0.028 in) 1.2 mm (0.047
in)
Side clearance (installed) 0.035–0.070 mm (0.0014~0.0028 in) 0.1 mm (0.004
in)
Crankshaft:
Crank width "A" 55.90–55.95 mm (2.201–2.203 in) ----
Runout limit "C" 0.03 mm (0.0012 in) 0.05 mm
(0.0020 in)
Connecting rod big end side clearance "D" 0.06–0.64 mm (0.002–0.025 in) ----
Small end free play "F" 0.8–1.0 mm (0.031–0.039 in) 2.0 mm (0.08
in)
Item Standard Limit
2-4
MAINTENANCE SPECIFICATIONS
Clutch:
Friction plate thickness 2.9–3.1 mm (0.114–0.122 in) 2.8 mm (0.110
in)
Quantity 8 ----
Clutch plate thickness 1.5–1.7 mm (0.059–0.067 in) ----
Quantity 7 ----
Warp limit ---- 0.2 mm (0.008
in)
Clutch spring free length 40.1 mm (1.579 in) 38.1 mm
(1.500 in)
Quantity 5 ----
Clutch housing thrust clearance 0.15–0.26 mm (0.006–0.010 in) ----
Clutch housing radial clearance 0.01–0.04 mm (0.0006–0.0018 in) ----
Clutch release method Inner push, cam push ----
Transmission:
Main axle deflection limit ---- 0.01 mm
(0.0004 in)
Drive axle deflection limit ---- 0.01 mm
(0.0004 in)
Shifter:
Shifting type Cam drum and guide bar ----
Guide bar bending limit ---- 0.05 mm
(0.0020 in)
Kick starter type: Kick and mesh type ----
Kick clip friction force P=0.8–1.2 kg (1.8–2.6 lb) ----
Air filter oil grade (oiled filter): Foam-air-filter oil or equivalent oil ----
Carburetor: USA, CDN EUROPE AUS, NZ, ZA
Type/Manufacturer TMXχ38SS/
MIKUNI
←←
I.D. mark 1C37 51 1C36 41 ----
Main jet (M.J.) #430 ←←----
Jet needle-clip position (J.N.) 6BFY43-74-3 ←←----
Cutaway (C.A.) 4.0 ←←----
Pilot jet (P.J.) #40 #45 ----
Pilot air screw (P.A.S.) 2-1/4 ←←----
Valve seat size (V.S.) ø3.8 mm (0.15
in)
←←----
Starter jet (G.S.) #80 ←←----
Fuel level (F.L.) 9.5–10.5 mm
(0.37–0.41 in)
←←----
Reed valve:
Thickness 0.47 mm (0.019 in) ----
Valve stopper height 8.2–8.6 mm (0.323–0.339 in) ----
Valve bending limit ---- 0.2 mm (0.008
in)
Item Standard Limit
2-5
MAINTENANCE SPECIFICATIONS
CHASSIS
Cooling:
Radiator core size:
Width 107.8 mm (4.24 in) ----
Height (left) 240 mm (9.45 in) ----
Height (right) 220 mm (8.66 in) ----
Thickness 32 mm (1.26 in) ----
Radiator cap opening pressure 95–125 kPa (0.95–1.25 kg/cm
2
, 13.5–17.8 psi) ----
Radiator capacity (total) 0.56 L (0.49 Imp qt, 0.59 US qt) ----
Water pump:
Type Single-suction centrifugal pump ----
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension: USA, CDN, ZA, AUS,
NZ
EUROPE
Front fork travel 300 mm (11.8 in) ----
Fork spring free length 454 mm (17.9 in) 449 mm (17.7
in)
Spring rate, STD K=4.1 N/mm (0.418
kg/mm, 23.4 lb/in)
----
Optional spring Yes ----
Oil capacity 524 cm
3
(18.4 Imp oz,
17.7 US oz)
526 cm
3
(18.5 Imp oz,
17.8 US oz)
----
Oil grade Suspension oil "S1" ----
Inner tube outer diameter 48 mm (1.9 in) ----
Front fork top end 5 mm (0.2 in) ----
Rear suspension: USA, CDN, ZA, AUS,
NZ
EUROPE
Shock absorber travel 131.5 mm (5.18 in) ----
Spring free length Approx. 265 mm (10.43
in)
----
Fitting length* ----
I.D. mark (Red/1) 258 mm (10.16 in) 252 mm (9.92 in) ----
I.D. mark (Red/2) 264 mm (10.39 in) 258 mm (10.16 in) ----
I.D. mark (Red/3) 255.5 mm (10.06 in) 249.5 mm (9.82 in) ----
Preload length
<Min.–Max> 1.5–18 mm (0.06–0.71
in)
----
Spring rate, STD K=46.0 N/mm (4.70
kg/mm, 263.2 lb/in)
----
Optional spring Yes ----
Enclosed gas pressure 1,000 kPa (10 kg/cm
2
,
142 psi)
----
* Spring specification varies according to the differ-
ence in the production lot.
Item Standard Limit
2-6
MAINTENANCE SPECIFICATIONS
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04
in)
Side clearance ---- 0.2–0.9 mm
(0.008–0.035
in)
Wheel:
Front wheel type Spoke wheel ----
Rear wheel type Spoke wheel ----
Front rim size/material 21 × 1.60/Aluminum ----
Rear rim size/material 19 × 1.85/Aluminum ----
Rim runout limit:
Radial ---- 2.0 mm (0.08
in)
Lateral ---- 2.0 mm (0.08
in)
Drive chain:
Type/manufacturer DID520DMA2 SDH G&B/DAIDO ----
Number of links 111 links + joint ----
Chain slack 48–58 mm (1.9–2.3 in) ----
Chain length (15 links) ---- 242.9 mm
(9.563 in)
Front disc brake:
Disc outside dia.×Thickness 250 × 3.0 mm (9.84 × 0.12 in) 250 × 2.5 mm
(9.84 × 0.10 in)
Pad thickness 4.4 mm (0.17 in) 1.0 mm (0.04
in)
Master cylinder inside dia. 9.52 mm (0.375 in) ----
Caliper cylinder inside dia. 22.65 mm (0.892 in) × 2 ----
Brake fluid type DOT #4 ----
Rear disc brake:
Disc outside dia.×Thickness 245 × 4.0 mm (9.65 × 0.16 in) 245 × 3.5 mm
(9.65 × 0.14 in)
Deflection limit ---- 0.15 mm
(0.006 in)
Pad thickness 6.4 mm (0.25 in) 1.0 mm (0.04
in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 25.4 mm (1.000 in) × 1 ----
Brake fluid type DOT #4 ----
Brake lever and brake pedal:
Brake lever position 95 mm (3.74 in) ----
Brake pedal height (vertical height above footrest
top)
0 mm (0 in) ----
Clutch lever free play (lever end) 8–13 mm (0.31–0.51 in) ----
Throttle grip free play 3–5 mm (0.12–0.20 in) ----
Item Standard Limit
2-7
TIGHTENING TORQUES
ELECTRICAL
TIGHTENING TORQUES
ENGINE
- marked portion shall be checked for torque tightening after break-in or before each race.
Item Standard Limit
Ignition system:
Ignition timing (B.T.D.C.) 0.48 mm (0.019 in) ----
Advancer type Electrical ----
CDI:
Magneto-model (stator)/Manufacturer 1C3-10/YAMAHA ----
Charging coil 1 resistance (color) 720–1,080 Ωat 20 °C (68 °F) (Green/
White-Black/Red)
----
Charging coil 2 resistance (color) 44–66 Ωat 20 °C (68 °F) (Black-Green/
Blue)
----
Pickup coil resistance (color) 248–372 Ωat 20 °C (68 °F) (White/Blue-
White/Red)
----
CDI unit-model/manufacturer 1C3-10/YAMAHA (USA, CDN)
1SR-00/YAMAHA (EUROPE, AUS, ZA,
NZ)
----
Ignition coil:
Model/manufacturer 1C3-00/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.24–0.36 Ωat 20 °C (68 °F) ----
Secondary winding resistance 5.7–8.5 kΩat 20 °C (68 °F) ----
Spark plug cap:
Resistance 4–6 kΩat 20 °C (68 °F) ----
Item
Thread
size
Q'ty Tightening torque Remarks
Spark plug M14S 1 20 Nm (2.0 m•kg, 14 ft•lb)
Cylinder head (nut) M8 5 28 Nm (2.8 m•kg, 20 ft•lb)
Copper
washer
Cylinder head (stud) M8 5 13 Nm (1.3 m•kg, 9.4 ft•lb)
Cylinder (nut) M8 4 30 Nm (3.0 m•kg, 22 ft•lb)
Cylinder (stud) M10 4 13 Nm (1.3 m•kg, 9.4 ft•lb)
Power valve:
Cover M5 4 5 Nm (0.5 m•kg, 3.6 ft•lb) YPVS
Link lever M4 1 4 Nm (0.4 m•kg, 2.9 ft•lb) YPVS
Holder (power valve) M5 4 8 Nm (0.8 m•kg, 5.8 ft•lb) YPVS
Push rod M5 1 5 Nm (0.5 m•kg, 3.6 ft•lb) YPVS
Thrust plate M5 1 4 Nm (0.4 m•kg, 2.9 ft•lb) YPVS
Governor fork M4 2 5 Nm (0.5 m•kg, 3.6 ft•lb) YPVS
Housing M5 3 4 Nm (0.4 m•kg, 2.9 ft•lb) YPVS
Water pump housing cover M6 4 10 Nm (1.0 m•kg, 7.2 ft•lb)
Coolant drain bolt M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Copper
washer
Radiator M6 6 10 Nm (1.0 m•kg, 7.2 ft•lb)
Radiator guard M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
2-8
TIGHTENING TORQUES
Radiator hose clamp M6 8 2 Nm (0.2 m•kg, 1.4 ft•lb)
Air filter element M6 1 2 Nm (0.2 m•kg, 1.4 ft•lb)
Carburetor joint M6 4 10 Nm (1.0 m•kg, 7.2 ft•lb)
Carburetor joint clamp M4 1 2 Nm (0.2 m•kg, 1.4 ft•lb)
Air filter joint clamp M4 1 2 Nm (0.2 m•kg, 1.4 ft•lb)
Air filter case M6 4 8 Nm (0.8 m•kg, 5.8 ft•lb)
Air filter guide clamp M5 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Reed valve M3 6 1 Nm (0.1 m•kg, 0.7 ft•lb)
Throttle cable adjust bolt and locknut M8 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Throttle cable M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Crankcase M6 12 14 Nm (1.4 m•kg, 10 ft•lb)
Right crankcase cover M6 8 10 Nm (1.0 m•kg, 7.2 ft•lb)
Left crankcase cover M6 4 5 Nm (0.5 m•kg, 3.6 ft•lb)
Drive chain sprocket cover M6 2 5 Nm (0.5 m•kg, 3.6 ft•lb)
Bearing plate cover M6 4 10 Nm (1.0 m•kg, 7.2 ft•lb)
Holder M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Oil check bolt M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Copper
washer
Oil drain bolt M10 1 20 Nm (2.0 m•kg, 14 ft•lb)
Copper
washer
Kickstarter crank M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Clutch cover M6 6 10 Nm (1.0 m•kg, 7.2 ft•lb)
Primary drive gear M8 1 48 Nm (4.8 m•kg, 35 ft•lb)
Clutch boss M16 1 80 Nm (8.0 m•kg, 58 ft•lb) Lock washer
Clutch spring M6 5 10 Nm (1.0 m•kg, 7.2 ft•lb)
Clutch cable adjust bolt and locknut M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Drive sprocket M18 1 75 Nm (7.5 m•kg, 54 ft•lb) Lock washer
Shift pedal M6 1 12 Nm (1.2 m•kg, 8.7 ft•lb)
Bearing plate cover (shift cam) M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Shift guide M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Stopper lever M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Segment M8 1 30 Nm (3.0 m•kg, 22 ft•lb)
Exhaust pipe M6 2 12 Nm (1.2 m•kg, 8.7 ft•lb)
Exhaust pipe stay (front) M6 1 12 Nm (1.2 m•kg, 8.7 ft•lb)
Exhaust pipe stay (rear) M6 1 12 Nm (1.2 m•kg, 8.7 ft•lb)
Silencer:
Silencer and frame M6 2 12 Nm (1.2 m•kg, 8.7 ft•lb)
Fiber M6 4 10 Nm (1.0 m•kg, 7.2 ft•lb)
Item
Thread
size
Q'ty Tightening torque Remarks
2-9
TIGHTENING TORQUES
CHASSIS
- marked portion shall be checked for torque tightening after break-in or before each race.
Item
Thread
size
Q'ty Tightening torque Remarks
Upper bracket and outer tube M8 4 21 Nm (2.1 m•kg, 15 ft•lb)
Lower bracket and outer tube M8 4 21 Nm (2.1 m•kg, 15 ft•lb)
Upper bracket and steering stem M24 1 145 Nm (14.5 m•kg, 105 ft•lb)
Handlebar upper holder M8 4 28 Nm (2.8 m•kg, 20 ft•lb)
Handlebar lower holder M12 2 40 Nm (4.0 m•kg, 29 ft•lb)
Steering ring nut M28 1 Refer to TIP.
Front fork and damper assembly M51 2 30 Nm (3.0 m•kg, 22 ft•lb)
Front fork and adjuster M22 2 55 Nm (5.5 m•kg, 40 ft•lb)
Copper
washer
Damper assembly and base valve M42 2 29 Nm (2.9 m•kg, 21 ft•lb)
Adjuster and damper assembly M12 2 29 Nm (2.9 m•kg, 21 ft•lb)
Bleed screw (front fork) and base valve M5 2 1 Nm (0.1 m•kg, 0.7 ft•lb)
Front fork and front fork protector M6 6 5 Nm (0.5 m•kg, 3.6 ft•lb)
Cable guide (front brake hose) and lower
bracket
M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Front fork protector and brake hose hold-
er
M6 2 8 Nm (0.8 m•kg, 5.8 ft•lb)
Throttle cable cap M4 2 0.5 Nm (0.05 m•kg, 0.36 ft•lb)
Front brake master cylinder and bracket M6 2 9 Nm (0.9 m•kg, 6.5 ft•lb)
Brake lever mounting bolt M6 1 6 Nm (0.6 m•kg, 4.3 ft•lb)
Brake lever mounting nut M6 1 6 Nm (0.6 m•kg, 4.3 ft•lb)
Brake lever position locknut M6 1 5 Nm (0.5 m•kg, 3.6 ft•lb)
Clutch lever mounting nut M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Clutch lever holder M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Front brake master cylinder cap M4 2 2 Nm (0.2 m•kg, 1.4 ft•lb)
Front brake hose union bolt (brake master
cylinder)
M10 1 30 Nm (3.0 m•kg, 22 ft•lb)
Copper
washer
Front brake hose union bolt (caliper) M10 1 30 Nm (3.0 m•kg, 22 ft•lb)
Copper
washer
Front brake caliper and front fork M8 2 28 Nm (2.8 m•kg, 20 ft•lb)
Grip cap upper and lower M6 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Engine stop switch screw M3 1 0.5 Nm (0.05 m•kg, 0.36 ft•lb)
Brake caliper (front and rear) and pad pin
plug
M10 2 3 Nm (0.3 m•kg, 2.2 ft•lb)
Brake caliper (front and rear) and pad pin M10 2 18 Nm (1.8 m•kg, 13 ft•lb)
Brake caliper (front and rear) and bleed
screw
M8 2 6 Nm (0.6 m•kg, 4.3 ft•lb)
Front wheel axle and axle nut M16 1 105 Nm (10.5 m•kg, 75 ft•lb)
Front wheel axle holder M8 4 21 Nm (2.1 m•kg, 15 ft•lb)
Front brake disc and wheel hub M6 6 12 Nm (1.2 m•kg, 8.7 ft•lb)
Rear brake disc and wheel hub M6 6 14 Nm (1.4 m•kg, 10 ft•lb)
2-10
TIGHTENING TORQUES
Footrest bracket and frame M10 4 55 Nm (5.5 m•kg, 40 ft•lb)
T O R X
Brake pedal mounting M8 1 26 Nm (2.6 m•kg, 19 ft•lb)
Rear brake master cylinder and frame M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Rear brake master cylinder cap M4 2 2 Nm (0.2 m•kg, 1.4 ft•lb)
Rear brake hose union bolt (caliper) M10 1 30 Nm (3.0 m•kg, 22 ft•lb)
Copper
washer
Rear brake hose union bolt (master cylin-
der)
M10 1 30 Nm (3.0 m•kg, 22 ft•lb)
Copper
washer
Rear wheel axle and axle nut M20 1 125 Nm (12.5 m•kg, 90 ft•lb)
Nipple (spoke) 72 3 Nm (0.3 m•kg, 2.2 ft•lb)
Driven sprocket and wheel hub M8 6 42 Nm (4.2 m•kg, 30 ft•lb)
Disc cover and rear brake caliper M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Protector and rear brake caliper M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Drive chain puller adjust bolt and locknut M8 2 19 Nm (1.9 m•kg, 13 ft•lb)
Engine:
Engine and frame (front) M10 1 64 Nm (6.4 m•kg, 46 ft•lb)
Engine and frame (lower) M10 1 64 Nm (6.4 m•kg, 46 ft•lb)
Engine bracket and frame M8 2 34 Nm (3.4 m•kg, 24 ft•lb)
Engine bracket and engine M8 1 34 Nm (3.4 m•kg, 24 ft•lb)
Pivot shaft and nut M16 1 85 Nm (8.5 m•kg, 61 ft•lb)
Relay arm and swingarm M14 1 70 Nm (7.0 m•kg, 50 ft•lb)
Relay arm and connecting rod M14 1 80 Nm (8.0 m•kg, 58 ft•lb)
Connecting rod and frame M14 1 80 Nm (8.0 m•kg, 58 ft•lb)
Rear shock absorber and frame M10 1 56 Nm (5.6 m•kg, 40 ft•lb)
Rear shock absorber and relay arm M10 1 53 Nm (5.3 m•kg, 38 ft•lb)
Rear shock absorber adjust locknut M56 1 30 Nm (3.0 m•kg, 22 ft•lb)
Rear frame and frame (upper) M8 1 32 Nm (3.2 m•kg, 23 ft•lb)
Rear frame and frame (lower) M8 2 29 Nm (2.9 m•kg, 21 ft•lb)
Swingarm and brake hose holder M5 4 3 Nm (0.3 m•kg, 2.2 ft•lb)
Swingarm and patch M4 4 2 Nm (0.2 m•kg, 1.4 ft•lb)
Drive chain tensioner M8 2 16 Nm (1.6 m•kg, 11 ft•lb)
Drive chain support and swingarm M6 3 7 Nm (0.7 m•kg, 5.1 ft•lb)
Seal guard and swingarm M5 4 6 Nm (0.6 m•kg, 4.3 ft•lb)
Cable guide and frame M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Fuel tank boss and frame M10 2 20 Nm (2.0 m•kg, 14 ft•lb)
Fuel tank M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Fuel tank and fuel cock M6 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Fuel tank and seat set bracket M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Fuel tank and hooking screw (fitting band) M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Fuel tank and fuel tank bracket M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
Air scoop and fuel tank M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
Air scoop and radiator guard (lower) M6 2 6 Nm (0.6 m•kg, 4.3 ft•lb)
Front fender M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
Item
Thread
size
Q'ty Tightening torque Remarks
2-11
TIGHTENING TORQUES
1. First, tighten the steering ring nut approximately 38 Nm (3.8 m•kg, 27 ft•lb) by using the steering nut wrench, then loosen
the steering ring nut one turn.
2. Retighten the steering ring nut 7 Nm (0.7 m•kg, 5.1 ft•lb).
ELECTRICAL
Rear fender (front) M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Rear fender (rear) M6 2 12 Nm (1.2 m•kg, 8.7 ft•lb)
Side cover M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Seat M8 2 19 Nm (1.9 m•kg, 13 ft•lb)
Number plate M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Item
Thread
size
Q'ty Tightening torque Remarks
Item
Thread
size
Q'ty Tightening torque Remarks
Stator M6 3 7 Nm (0.7 m•kg, 5.1 ft•lb)
Rotor M12 1 56 Nm (5.6 m•kg, 40 ft•lb)
Ignition coil M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
2-12
TIGHTENING TORQUES
GENERAL TORQUE
SPECIFICATIONS
This chart specifies torque for stan-
dard fasteners with standard I.S.O.
pitch threads. Torque specifications
for special components or assem-
blies are included in the applicable
sections of this book. To avoid warp-
age, tighten multi-fastener assem-
blies in a crisscross fashion, in
progressive stages, until full torque is
reached. Unless otherwise specified,
torque specifications call for clean,
dry threads. Components should be
at room temperature.
A. Distance between flats
B. Outside thread diameter
DEFINITION OF UNITS
A
(Nut)
B
(Bolt
)
TORQUE SPECIFI-
CATION
Nm m•kg ft•lb
10
mm
6 mm 6 0.6 4.3
12
mm
8 mm 15 1.5 11
14
mm
10
mm
30 3.0 22
17
mm
12
mm
55 5.5 40
19
mm
14
mm
85 8.5 61
22
mm
16
mm
130 13 94
Unit Read Definition Measure
mm
millimeter 10
-3
meter Length
cm
centimeter 10
-2
meter Length
kg
kilogram 10
3
gram Weight
N
Newton 1 kg × m/sec
2
Force
Nm
Newton meter N × m Torque
m•kg
Meter kilogram m × kg Torque
Pa
Pascal N/m
2
Pressure
N/mm
Newton per millimeter N/mm Spring rate
L
Liter Volume or capacity
cm
3
Cubic centimeter Volume or capacity
r/min
Revolution per minute Engine speed
2-13
CABLE ROUTING DIAGRAM
CABLE ROUTING DIAGRAM
1. Engine stop switch lead
2. Throttle cable
3. Clutch cable
4. Ground lead
5. High tension cord
6. Clamp
7. Air vent hose
8. Radiator breather hose
9. CDI magneto lead
10. YPVS breather hose
11. Engine bracket (right)
12. Engine bracket (left)
13. Crankcase breather hose
14. Overflow hose
15. Connector cover
A. Pass the clutch cable on the out-
side of the throttle cable and en-
gine stop switch lead.
B. Align the throttle cable locating
tape with the cable guide.
C. Pass the throttle cable, clutch
cable and engine stop switch
lead above the radiator hose.
2-14
CABLE ROUTING DIAGRAM
D. Install the ignition coil, side core
and ground lead together to the
frame. Take care to fasten the
ground lead so that its terminal
is within the indicated range.
E. Clamp the throttle cable and
high tension cord to the frame.
F. Clamp the clutch cable to the left
engine bracket. Clamp the
clutch cable below the position-
ing grommet.
G. Pass the air vent hose back of
the throttle cable.
H. Pass the air vent hose, overflow
hose and crankcase breather
hose between the frame and
connecting rod.
I. Pass the radiator breather hose
and YPVS breather hose out-
side the engine bracket and in-
side the down tube. Then pass
the radiator breather hose inside
the YPVS breather hose.
J. Clamp the CDI magneto lead,
radiator breather hose and
YPVS breather hose to the
frame.
K. Clamp to the frame the CDI
magneto lead and radiator
breather hose. Take care to
clamp them above the projection
on the frame.
L. Locate the clamp ends in the ar-
rowed range.
M. Direct the clip with its finger grip
facing forward.
N. Tighten the clamp with its bolt
head facing the left side of the
chassis (on both sides of the
carburetor joint and the air filter
joint).
O. Pass the air vent hose, overflow
hose and crankcase breather
hose so that they do not contact
the rear shock absorber.
P. Bring the connector cover into
contact with the coupler.
2-15
CABLE ROUTING DIAGRAM
1. High tension cord
2. Engine stop switch lead
3. Ignition coil lead
4. Clamp
5. CDI unit
6. CDI unit band
7. Radiator breather hose
8. CDI magneto lead
9. Connector cover
10. Throttle cable
11. Clutch cable
12. CDI unit stay
A. Pass the high tension cord to the
left of the radiator hose.
B. Using a plastic locking tie, clamp
the engine stop switch lead, igni-
tion coil lead and CDI magneto
lead together with the clamp
ends backward and then cut off
the tie end.
C. Clamp to the frame the throttle
cable, clutch cable, ignition coil
lead and engine stop switch
lead. In so doing, clamp the igni-
tion coil lead and engine stop
switch lead at their protecting
tubes. Tighten the clamp so that
the engine stop switch lead is
not pulled when the handlebar is
turned to the right and left.
2-16
CABLE ROUTING DIAGRAM
D. Pass the CDI magneto lead and
radiator breather hose between
the frame and the radiator
(right).
E. Clamp the CDI magneto lead to
the frame at its locating tape.
F. Bring the connector cover into
contact with the coupler.
G. Locate the clamp ends in the ar-
rowed range.
H. Insert the CDI unit band until it
stops at the CDI unit stay.
I. Pass the CDI magneto lead and
radiator breather hose between
the frame and the radiator hose
so that they come within the ar-
row-indicated range. Also take
care so that the CDI magneto
lead passes on the left of the ra-
diator breather hose.
2-17
CABLE ROUTING DIAGRAM
1. Master cylinder
2. Brake hose holder
3. Brake hose
A. Install the brake hose so that its
pipe portion directs as shown
and lightly touches the projec-
tion on the caliper.
B. Pass the brake hose into the
brake hose holders.
C. If the brake hose contacts the
spring (rear shock absorber),
correct its twist.
D. Install the brake hose so that its
pipe portion directs as shown
and lightly touches the projec-
tion on the master cylinder.
2-18
CABLE ROUTING DIAGRAM
1. Brake hose
2. Master cylinder
3. Engine stop switch lead
4. Engine stop switch
5. Throttle cable
6. Clutch cable
7. Clamp
8. Cable guide
A. Install the brake hose so that its
pipe portion directs as shown
and lightly touches the projec-
tion on the master cylinder.
B. Pass the engine stop switch
lead in the middle of the clutch
holder.
C. Clamp the engine stop switch
lead to the handlebar.
D. Pass the brake hose in front of
the number plate and through
the cable guide.
E. Pass the clutch cable through
the cable guide on the number
plate.
(0.55 in)
(0.47 in)
3-1
MAINTENANCE INTERVALS
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind that such factors as
weather, terrain, geographical location, and individual usage will alter the required maintenance and lubrication intervals.
If you are a doubt as to what intervals to follow in maintaining and lubricating your machine, consult your Yamaha dealer.
Periodic inspection is essential in making full use of the machine performance. The service life of the parts varies sub-
stantially according to the environment in which the machine runs (e.g., rain, dirt, etc.). Therefore, earlier inspection is
required by reference to the list below.
Item
After
break-in
Every
race
(about
2.5
hours)
Every
third
(about
7.5
hours)
Every
fifth
(about
12.5
hours)
As re-
quired
Remarks
PISTON
Inspect and clean ●● Inspect crack.
Replace ●●Inspect carbon deposits and
eliminate them.
PISTON RING
Inspect ●● Check ring end gap.
Replace ●●
PISTON PIN, SMALL END
BEARING
Inspect
Replace
CYLINDER HEAD Inspect carbon deposits and
eliminate them.
Inspect and clean ●● Check gasket.
Retighten ●●
CYLINDER
Inspect and clean ●● Inspect score marks.
Replace Inspect wear.
YPVS
Inspect and clean ●● Inspect carbon deposits and
eliminate them.
CLUTCH
Inspect and adjust ●● Inspect housing, friction plate,
clutch plate and spring.
Replace
TRANSMISSION
Replace oil ●●Recommended brand: YAMA-
LUBE
SAE10W-40
API service SG type or higher
JASO standard MA
Inspect
Replace bearing
SHIFT FORK, SHIFT CAM,
GUIDE BAR
Inspect Inspect wear.
3-2
MAINTENANCE INTERVALS
ROTOR NUT
Retighten ●●
MUFFLER
Inspect ●●
Clean
Retighten ●●
Replace fiber ●* * When the exhaust sound be-
comes louder or when a per-
formance drop is felt.
CRANK
Inspect and clean ●●
CARBURETOR
Inspect, adjust and clean ●●
SPARK PLUG
Inspect and clean ●●
Replace
DRIVE CHAIN Use chain lube.
Lubricate, slack, alignment ●● Chain slack: 48–58 mm (1.9–
2.3 in)
Replace
COOLING SYSTEM
Check coolant level and
leakage
●●
Check radiator cap opera-
tion
Replace coolant Every two years
Inspect hoses
OUTSIDE NUTS AND
BOLTS
Retighten ●● Refer to "STARTING AND
BREAK-IN" section in the
CHAPTER 1.
AIR FILTER
Clean and lubricate ●● Use foam air-filter oil or equiv-
alent oil.
Replace
FRAME
Clean and inspect ●●
FUEL TANK, COCK
Clean and inspect ●●
Item
After
break-in
Every
race
(about
2.5
hours)
Every
third
(about
7.5
hours)
Every
fifth
(about
12.5
hours)
As re-
quired
Remarks
3
3-3
MAINTENANCE INTERVALS
BRAKES
Adjust lever position and
pedal height
●●
Lubricate pivot point ●●
Check brake disc surface ●●
Check fluid level and leak-
age
●●
Retighten brake disc bolts,
caliper bolts, master cylin-
der bolts and union bolts
●●
Replace pads
Replace brake fluid Every one year
FRONT FORKS
Inspect and adjust ●●
Replace oil ●●Suspension oil "S1"
Replace oil seal
FRONT FORK OIL SEAL
AND DUST SEAL
Clean and lube ●● Lithium base grease
PROTECTOR GUIDE
Replace
REAR SHOCK ABSORBER
Inspect and adjust ●●
Lube
(After rain
ride)
Molybdenum disulfide grease
Replace spring seat Every one year
Retighten ●●
DRIVE CHAIN GUIDE AND
ROLLERS
Inspect ●●
SWINGARM
Inspect, lube and retighten ●● Molybdenum disulfide grease
RELAY ARM, CONNECT-
ING ROD
Inspect, lube and retighten ●● Molybdenum disulfide grease
STEERING HEAD
Inspect free play and re-
tighten
●●
Clean and lube Lithium base grease
Replace bearing
Item
After
break-in
Every
race
(about
2.5
hours)
Every
third
(about
7.5
hours)
Every
fifth
(about
12.5
hours)
As re-
quired
Remarks
3-4
MAINTENANCE INTERVALS
TIRE, WHEELS
Inspect air pressure, wheel
run-out, tire wear and
spoke looseness
●●
Retighten sprocket bolt ●●
Inspect bearings
Replace bearings
Lubricate Lithium base grease
THROTTLE, CONTROL CA-
BLE
Check routing and connec-
tion
●●
Lubricate ●● Yamaha cable lube or SAE
10W-40 motor oil
Item
After
break-in
Every
race
(about
2.5
hours)
Every
third
(about
7.5
hours)
Every
fifth
(about
12.5
hours)
As re-
quired
Remarks
3-5
PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
Coolant
Check that coolant is filled up to the radiator cap. Check the cool-
ing system for leakage.
P.3-6 – 7
Fuel
Check that a fresh mixture of oil and gasoline is filled in the fuel
tank. Check the fuel line for leakage.
P.1-12
Transmission oil
Check that the oil level is correct. Check the crankcase for leak-
age.
P.3-8 – 9
Gear shifter and clutch
Check that gears can be shifted correctly in order and that the
clutch operates smoothly.
P.3-7
Throttle grip/Housing
Check that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.
P.3-7 – 8
Brakes Check the play of front brake and effect of front and rear brake. P.3-9 – 12
Drive chain
Check drive chain slack and alignment. Check that the drive chain
is lubricated properly.
P.3-12 – 13
Wheels
Check for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.
P.3-16 – 17
Steering
Check that the handlebar can be turned smoothly and have no ex-
cessive play.
P.3-17
Front forks and rear shock
absorber
Check that they operate smoothly and there is no oil leakage.
P.3-13 – 16
Cables (wires)
Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or when
the front forks travel up and down.
Muffler Check that the muffler is tightly mounted and has no cracks. P.4-3 – 4
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-12
Lubrication Check for smooth operation. Lubricate if necessary. P.3-18
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-13
Lead connectors
Check that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.
P.1-7
Settings
Is the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs be-
fore racing? Are inspection and maintenance completely done?
P.7-1 – 11
3-6
ENGINE
ENGINE
CHECKING THE COOLANT LEVEL
Do not remove the radiator cap
"1", drain bolt and hoses when the
engine and radiator are hot. Scald-
ing hot fluid and steam may be
blown out under pressure, which
could cause serious injury. When
the engine has cooled, place a
thick towel over the radiator cap,
slowly rotate the cap counter-
clockwise to the detent. This pro-
cedure allows any residual
pressure to escape. When the
hissing sound has stopped, press
down on the cap while turning
counterclockwise and remove it.
Hard water or salt water is harmful
to the engine parts. You may use
distilled water, if you can't get soft
water.
1. Place the machine on a level
place, and hold it in an upright po-
sition.
2. Remove:
Radiator cap
3. Check:
Coolant level "a"
Coolant level low Add coolant.
1. Radiator
CHANGING THE COOLANT
Do not remove the radiator cap
when the engine is hot.
Take care so that coolant does not
splash on painted surfaces. If it
splashes, wash it away with water.
1. Place a container under the en-
gine.
2. Remove:
Coolant drain bolt "1"
3. Remove:
Radiator cap
Drain the coolant completely.
4. Clean:
Cooling system
Thoroughly flush the cooling sys-
tem with clean tap water.
5. Install:
Copper washer
Coolant drain bolt
6. Fill:
Radiator
•Engine
To specified level.
Do not mix more than one type of
ethylene glycol antifreeze con-
taining corrosion inhibitors for
aluminum engine.
Do not use water containing im-
purities or oil.
Handling notes of coolant:
The coolant is harmful so it should be
handled with special care.
When coolant splashes to your
eye.
Thoroughly wash your eye with
water and see your doctor.
When coolant splashes to your
clothes.
Quickly wash it away with water
and then with soap.
When coolant is swallowed.
Quickly make him vomit and take
him to a doctor.
7. Install:
Radiator cap
Start the engine and warm it up
for a several minutes.
8. Check:
Coolant level
Coolant level low Add coolant.
CHECKING THE RADIATOR CAP
1. Inspect:
Seal (radiator cap) "1"
Valve and valve seat "2"
Crack/damage Replace.
Exist fur deposits "3" Clean or
replace.
CHECKING THE RADIATOR CAP
OPENING PRESSURE
1. Attach:
Radiator cap tester "1" and adapt-
er "2"
Apply water on the radiator cap seal.
Coolant drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Recommended coolant:
High quality ethylene
glycol anti-freeze con-
taining anti-corrosion
for aluminum engine
Coolant "1" and water
(soft water) "2" mixing ra-
tio:
50%/50%
Coolant capacity:
0.9 L (0.79 Imp qt, 0.95
US qt)
Radiator cap tester:
YU-24460-01/90890-
01325
Radiator cap tester
adapter:
YU-33984/90890-01352
3-7
ENGINE
3. Radiator cap
2. Apply the specified pressure.
3. Inspect:
Pressure
Impossible to maintain the speci-
fied pressure for 10 seconds
Replace.
CHECKING THE COOLING
SYSTEM
1. Inspect:
Coolant level
2. Attach:
Radiator cap tester "1" and adapt-
er "2"
3. Apply the specified pressure.
Do not apply pressure more than
specified pressure.
Radiator should be filled fully.
4. Inspect:
Pressure
Impossible to maintain the speci-
fied pressure for 10 seconds
Repair.
•Radiator "1"
Radiator hose joint "2"
Coolant leakage Repair or re-
place.
Radiator hose "3"
Swelling Replace.
ADJUSTING THE CLUTCH LEVER
FREE PLAY
1. Check:
Clutch lever free play "a"
Out of specification Adjust.
2. Adjust:
Clutch lever free play
Clutch lever free play adjustment
steps:
a. Loosen the locknuts "1".
b. Turn the adjuster "2" until free
play "a" is within the specified lim-
its.
c. Tighten the locknuts.
Before adjustment, expose the ad-
juster by moving the boot "3" and
cap "4" away.
Make minute adjustment on the le-
ver side using the adjuster "5".
After adjustment, check proper op-
eration of clutch lever.
3. Install:
Cap "1"
•Boot "2"
Place the tip "a" of the cap in the boot.
ADJUSTING THE THROTTLE GRIP
FREE PLAY
1. Check:
Throttle grip free play "a"
Out of specification Adjust.
2. Adjust:
Throttle grip free play
Adjustment steps:
a. Slide the adjuster cover.
b. Loosen the locknut "1".
c. Turn the adjuster "2" until the
specified free play is obtained.
d. Tighten the locknut.
Prior to adjusting throttle grip free
play, the engine idling speed should
be adjusted.
After adjusting the throttle grip
free play, turn the handlebar to the
right and to the left to ensure that
this does not cause the engine
idling speed to change.
Radiator cap opening
pressure:
95–125 kPa (0.95–1.25
kg/cm
2
, 13.5–17.8 psi)
Radiator cap tester:
YU-24460-01/90890-
01325
Radiator cap tester
adapter:
YU-33984/90890-01352
Standard pressure:
180 kPa (1.8 kg/cm
2
,
25.6 psi)
Clutch lever free play "a"
:
8–13 mm (0.31–0.51 in)
Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Throttle grip free play
"a":
3–5 mm (0.12–0.20 in)
Locknut:
7 Nm (0.7 m•kg, 5.1
ft•lb)
3-8
ENGINE
LUBRICATING THE THROTTLE
1. Remove:
Cap cover "1"
Throttle cable cap "2"
2. Apply:
Lithium soap base grease
On the throttle cable end "a", tube
guide cable winding portion "b"
and roller sliding surface "c".
3. Install:
Throttle cable cap
Cap cover
CLEANING THE AIR FILTER
ELEMENT
Proper air filter maintenance is the
biggest key to preventing premature
engine wear and damage.
Never run the engine without the
air filter element in place; this
would allow dirt and dust to enter
the engine and cause rapid wear
and possible engine damage.
1. Remove:
Seat
Fitting bolt "1"
Washer "2"
Air filter element "3"
Air filter guide "4"
2. Clean:
Air filter element
Clean them with solvent.
After cleaning, remove the remaining
solvent by squeezing the element.
Do not twist the element when
squeezing the element.
Leaving too much of solvent in
the element may result in poor
starting.
3. Inspect:
Air filter element
Damage Replace.
4. Apply:
Foam-air-filter oil or equivalent oil
to the element
Squeeze out the excess oil. Element
should be wet but not dripping.
5. Install:
Air filter guide "1"
Align the projection "a" on filter guide
with the hole "b" in air filter element.
6. Apply:
Lithium soap base grease
On the matching surface "a" on air
filter element.
7. Install:
Air filter element "1"
Washer
Fitting bolt
Align the projection "a" on filter guide
with the hole "b" in air filter case.
CHECKING THE TRANSMISSION
OIL LEVEL
1. Start the engine, warm it up for
several minutes and wait for five
minutes.
2. Place the machine on a level
place and hold it up on upright po-
sition by placing the suitable
stand under the engine.
3. Check:
Transmission oil level
Transmission oil level checking
steps:
a. Remove the oil check bolt "1".
b. Inspect the oil level.
Be sure the machine is positioned
straight up when inspecting the oil
level.
Never attempt to remove the oil
check bolt just after high speed
operation. The heated oil could
spout out, causing danger. Wait
until the oil cools down.
Oil flows out Oil level is correct.
Oil does not flow out Oil level
is low. Add transmission oil until
oil flows out.
Throttle cable cap:
0.5 Nm (0.05 m•kg, 0.36
ft•lb)
Fitting bolt:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Recommended brand:
YAMALUBE
Recommended engine
oil type
SAE10W-40
Recommended engine
oil grade
API service SG type or
higher
JASO standard MA
3-9
CHASSIS
c. Inspect the gasket (oil check bolt),
replace if damaged.
d. Tighten the oil check bolt.
CHANGING THE TRANSMISSION
OIL
1. Start the engine and warm it up
for several minutes and wait for
five minute.
2. Place the machine on a level
place and hold it on upright posi-
tion by placing the suitable stand
under the engine.
3. Place a suitable container under
the engine.
4. Remove:
Oil drain bolt "1"
Oil filler cap "2"
Drain the transmission oil.
5. Install:
Aluminum washer
Oil drain bolt "1"
6. Fill:
Transmission oil
7. Check:
Oil leakage
8. Check:
Transmission oil level
9. Install:
Oil filler cap "2"
ADJUSTING THE PILOT AIR
SCREW
1. Adjust:
Pilot air screw "1"
Adjustment steps:
a. Screw in the pilot air screw until it
is lightly seated.
b. Back out by the specified number
of turns.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly
warm it up.
2. Adjust:
Engine idling speed
Adjustment steps:
a. Loosen the locknut "1".
b. Turn the throttle stop screw "2"
until the engine runs at the lowest
possible speed.
c. Tighten the locknut.
CHECKING THE EXHAUST PIPE
1. Inspect:
O-ring "1"
Damage Replace.
Install the O-rings with their de-
pressed "a" facing outward.
CHASSIS
BLEEDING THE HYDRAULIC
BRAKE SYSTEM
Bleed the brake system if:
The system has been disassem-
bled.
A brake hose has been loosened
or removed.
The brake fluid is very low.
The brake operation is faulty.
A dangerous loss of braking per-
formance may occur if the brake
system is not properly bled.
1. Remove:
Brake master cylinder cap
Diaphragm
Reservoir float (front brake)
Protector (rear brake)
2. Bleed:
Brake fluid
Air bleeding steps:
a. Add proper brake fluid to the res-
ervoir.
b. Install the diaphragm. Be careful
not to spill any fluid or allow the
reservoir to overflow.
c. Connect the clear plastic tube "2"
tightly to the caliper bleed screw
"1".
Oil check bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil drain bolt:
20 Nm (2.0 m•kg, 14
ft•lb)
Recommended brand:
YAMALUBE
Recommended engine
oil type
SAE10W-40
Recommended engine
oil grade
API service SG type or
higher
JASO standard MA
Oil capacity (periodic oil
change):
0.66 L (0.58 Imp qt, 0.69
US qt)
Pilot air screw:
2-1/4 turns out
To increase idle speedTurn the
throttle stop screw "2" in.
To decrease idle speedTurn the
throttle stop screw "2" out.
3-10
CHASSIS
A. Front
B. Rear
d. Place the other end of the tube
into a container.
e. Slowly apply the brake lever or
pedal several times.
f. Pull the lever in or push down on
the pedal. Hold the lever or pedal
in position.
g. Loosen the bleed screw and allow
the lever or pedal to travel to-
wards its limit.
h. Tighten the bleed screw when the
lever or pedal limit has been
reached; then release the lever or
pedal.
i. Repeat steps (e) to (h) until of the
air bubbles have been removed
from the system.
If bleeding is difficult, it may be nec-
essary to let the brake fluid system
stabilize for a few hours. Repeat the
bleeding procedure when the tiny
bubbles in the system have disap-
peared.
j. Add brake fluid to the level line on
the reservoir.
Check the operation of the brake
after bleeding the brake system.
3. Install:
Protector (rear brake)
Reservoir float (front brake)
Diaphragm
Brake master cylinder cap
ADJUSTING THE FRONT BRAKE
1. Check:
Brake lever position "a"
2. Remove:
Brake lever cover
3. Adjust:
Brake lever position
Brake lever position adjustment
steps:
a. Loosen the locknut "1".
b. Turn the adjusting bolt "2" until the
lever position "a" is within speci-
fied position.
c. Tighten the locknut.
Be sure to tighten the locknut, as it
will cause poor brake perfor-
mance.
4. Install:
Brake lever cover
ADJUSTING THE REAR BRAKE
1. Check:
Brake pedal height "a"
Out of specification Adjust.
2. Adjust:
Brake pedal height
Pedal height adjustment steps:
a. Loosen the locknut "1".
b. Turn the adjusting nut "2" until the
pedal height "a" is within specified
height.
c. Tighten the locknut.
Adjust the pedal height between
the maximum "A" and the mini-
mum "B" as shown. (In this ad-
justment, the bolt "3" end "b"
should protrude out of the
threaded portion "4" but not be
less than 2 mm (0.08 in) "c" away
from the brake pedal "5").
After the pedal height adjust-
ment, make sure that the rear
brake does not drag.
CHECKING AND REPLACING THE
FRONT BRAKE PADS
1. Inspect:
Brake pad thickness "a"
Out of specification Replace as
a set.
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Brake lever position "a":
Standard posi-
tion
Extent of ad-
justment
95 mm (3.74 in)
86–105 mm
(3.39–4.13 in)
Locknut:
5 Nm (0.5 m •kg, 3.6
ft•lb)
Brake pedal height "a":
0 mm (0 in)
Brake pad thickness "a":
4.4 mm (0.17 in)
<Limit>: 1.0 mm (0.04
in)
3-11
CHASSIS
2. Replace:
Brake pad
Brake pad replacement steps:
a. Remove the pad pin plug "1".
b. Loosen the pad pin "2".
c. Remove the brake caliper "3"
from the front fork.
d. Remove the pad pin and brake
pads "4".
e. Connect the transparent hose "5"
to the bleed screw "6" and place
the suitable container under its
end.
f. Loosen the bleed screw and push
the brake caliper pistons in.
Do not reuse the drained brake flu-
id.
g. Tighten the bleed screw.
h. Install the brake pads "7" and pad
pin.
Install the brake pads with their pro-
jections "a" into the brake caliper re-
cesses "b".
Temporarily tighten the pad pin at
this point.
i. Install the brake caliper "8" and
tighten the pad pin "9".
j. Install the pad pin plug "10".
3. Inspect:
Brake fluid level
Refer to "CHECKING THE
BRAKE FLUID LEVEL" section.
4. Check:
Brake lever operation
A softy or spongy feeling Bleed
brake system.
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion.
CHECKING AND REPLACING THE
REAR BRAKE PADS
1. Inspect:
Brake pad thickness "a"
Out of specification Replace as
a set.
2. Replace:
Brake pad
Brake pad replacement steps:
a. Remove the protector "1" and pad
pin plug "2".
b. Loosen the pad pin "3".
c. Remove the rear wheel "4" and
brake caliper "5".
Refer to "FRONT WHEEL AND
REAR WHEEL" section in the
CHAPTER 5.
d. Remove the pad pin "6" and brake
pads "7".
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Bolt (brake caliper):
28 Nm (2.8 m•kg, 20
ft•lb)
Pad pin:
18 Nm (1.8 m•kg, 13
ft•lb)
Pad pin plug:
3 Nm (0.3 m•kg, 2.2
ft•lb)
Brake pad thickness "a":
6.4 mm (0.25 in)
<Limit>: 1.0 mm (0.04
in)
3-12
CHASSIS
e. Connect the transparent hose "8"
to the bleed screw "9" and place
the suitable container under its
end.
f. Loosen the bleed screw and push
the brake caliper piston in.
Do not reuse the drained brake flu-
id.
g. Tighten the bleed screw.
h. Install the brake pads "10" and
pad pin "11".
Install the brake pads with their pro-
jections "a" into the brake caliper re-
cesses "b".
Temporarily tighten the pad pin at
this point.
i. Install the brake caliper "12" and
rear wheel "13".
Refer to "FRONT WHEEL AND
REAR WHEEL" section in the
CHAPTER 5.
j. Tighten the pad pin "14".
k. Install the pad pin plug "15" and
protector "16".
3. Inspect:
Brake fluid level
Refer to "CHECKING THE
BRAKE FLUID LEVEL" section.
4. Check:
Brake pedal operation
A softy or spongy feeling Bleed
brake system.
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion.
CHECKING THE REAR BRAKE
PAD INSULATOR
1. Remove:
•Brake pad
Refer to "CHECKING AND RE-
PLACING THE REAR BRAKE
PADS" section.
2. Inspect:
Rear brake pad insulator "1"
Damage Replace.
CHECKING THE BRAKE FLUID
LEVEL
1. Place the brake master cylinder
so that its top is in a horizontal po-
sition.
2. Inspect:
Brake fluid level
Fluid at lower level Fill up.
Use only designated quality
brake fluid to avoid poor brake
performance.
Refill with same type and brand
of brake fluid; mixing fluids
could result in poor brake perfor-
mance.
Be sure that water or other con-
taminants do not enter master
cylinder when refilling.
Clean up spilled fluid immediate-
ly to avoid erosion of painted
surfaces or plastic parts.
a. Lower level
A. Front
B. Rear
CHECKING THE SPROCKET
1. Inspect:
Sprocket teeth "a"
Excessive wear Replace.
Replace the drive sprocket, rear
wheel sprocket and drive chain as a
set.
CHECKING THE DRIVE CHAIN
1. Measure:
Drive chain length (15 links) "a"
Out of specification Replace.
While measuring the drive chain
length, push down on the drive
chain to increase its tension.
Measure the length between drive
chain roller "1" and "16" as shown.
Perform this measurement at two or
three different places.
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Pad pin:
18 Nm (1.8 m•kg, 13
ft•lb)
Pad pin plug:
3 Nm (0.3 m•kg, 2.2
ft•lb)
Bolt (protector):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Recommended brake flu-
id:
DOT #4
Drive chain length (15
links):
<Limit>: 242.9 mm
(9.563 in)
3-13
CHASSIS
2. Remove:
Master link clip
•Joint "1"
Drive chain "2"
3. Clean:
Drive chain
Place it in kerosene, and brush off
as much dirt as possible. Then re-
move the drive chain from the ker-
osene and dry the drive chain.
4. Check:
Drive chain stiffness "a"
Clean and oil the drive chain and
hold as illustrated.
Stiff Replace the drive chain.
5. Install:
Drive chain "1"
•Joint "2"
Master link clip "3"
Be sure to install the master link
clip to the direction as shown.
a. Turning direction
6. Lubricate:
Drive chain
ADJUSTING THE DRIVE CHAIN
SLACK
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Check:
Drive chain slack "a"
Above the seal guard installation
bolt.
Out of specification Adjust.
Before checking and/or adjusting, ro-
tate the rear wheel through several
revolutions and check the slack sev-
eral times to find the tightest point.
Check and/or adjust the drive chain
slack with the rear wheel in this "tight
chain" position.
3. Adjust:
Drive chain slack
Drive chain slack adjustment
steps:
a. Loosen the axle nut "1" and lock-
nuts "2".
b. Adjust the drive chain slack by
turning the adjusters "3".
c. Turn each adjuster exactly the
same amount to maintain correct
axle alignment. (There are marks
"a" on each side of the drive chain
puller alignment.) NOTICE: Im-
proper drive chain slack will
overload the engine as well as
other vital parts of the motorcy-
cle and can lead to chain slip-
page or breakage. To prevent
this from occurring, keep the
drive chain slack within the
specified limits.
Turn the adjuster so that the drive
chain is in line with the sprocket, as
viewed from the rear.
d. Tighten the axle nut while pushing
down the drive chain.
e. Tighten the locknuts.
CHECKING THE FRONT FORK
1. Inspect:
Front fork smooth action
Operate the front brake and
stroke the front fork.
Unsmooth action/oil leakage
Repair or replace.
Drive chain lubricant:
SAE 10W-40 motor oil
or suitable chain lubri-
cants
Drive chain slack "a":
48–58 mm (1.9–2.3 in)
To tightenTurn the adjuster "3"
counterclockwise.
To loosenTurn the adjuster "3"
clockwise and push wheel for-
ward.
Axle nut:
125 Nm (12.5 m•kg, 90
ft•lb)
Locknut:
19 Nm (1.9 m•kg, 13
ft•lb)
3-14
CHASSIS
CLEANING THE FRONT FORK OIL
SEAL AND DUST SEAL
1. Remove:
•Protector
Dust seal "1"
Use a thin screw driver, and be care-
ful not to damage the inner fork tube
and dust seal.
2. Clean:
Dust seal "a"
Oil seal "b"
Clean the dust seal and oil seal af-
ter every run.
Apply the lithium soap base grease
on the inner tube.
RELIEVING THE FRONT FORK
INTERNAL PRESSURE
If the front fork initial movement feels
stiff during a run, relieve the front fork
internal pressure.
1. Elevate the front wheel by placing
a suitable stand under the engine.
2. Remove the air bleed screw "1"
and release the internal pressure
from the front fork.
3. Install:
Air bleed screw
ADJUSTING THE FRONT FORK
REBOUND DAMPING FORCE
1. Adjust:
Rebound damping force
By turning the adjuster "1".
STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
ADJUSTING THE FRONT FORK
COMPRESSION DAMPING FORCE
1. Adjust:
Compression damping force
By turning the adjuster "1".
STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
CHECKING THE REAR SHOCK
ABSORBER
1. Inspect:
Swingarm smooth action
Abnormal noise/unsmooth action
Grease the pivoting points or
repair the pivoting points.
Damage/oil leakage Replace.
ADJUSTING THE REAR SHOCK
ABSORBER SPRING PRELOAD
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Remove:
Rear frame
Air bleed screw:
1 Nm (0.1 m•kg, 0.7
ft•lb)
Stiffer "a" Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b" Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position
20 clicks out
(from maximum
position)
Standard position:
14 clicks out
* 13 clicks out
* For EUROPE
Stiffer "a" Increase the com-
pression damping force. (Turn
the adjuster "1" in.)
Softer "b" Decrease the com-
pression damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position
20 clicks out
(from maximum
position)
Standard position:
13 clicks out
* 12 clicks out
* For EUROPE
3-15
CHASSIS
3. Measure:
Spring fitting length
The I.D. mark "a" is marked at the
end of the spring.
Spring specification varies accord-
ing to the difference in the produc-
tion lot.
4. Adjust:
Spring preload
Adjustment steps:
a. Loosen the locknut "1".
b. Loosen the adjuster "2" until there
is some clearance between the
spring and adjuster.
c. Measure the spring free length
"a".
d. Turn the adjuster "2".
Be sure to remove all dirt and mud
from around the locknut and adjust-
er before adjustment.
The length of the spring (installed)
changes 1.5 mm (0.06 in) per turn
of the adjuster.
Never attempt to turn the adjuster
beyond the maximum or minimum
setting.
e. Tighten the locknut.
5. Install:
Rear frame (upper)
Rear frame (lower)
ADJUSTING THE REAR SHOCK
ABSORBER REBOUND DAMPING
FORCE
1. Adjust:
Rebound damping force
By turning the adjuster "1".
STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
(Which align the punch mark "a"
on the adjuster with the punch
mark "b" on the bracket.)
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
ADJUSTING THE REAR SHOCK
ABSORBER LOW COMPRESSION
DAMPING FORCE
1. Adjust:
Low compression damping force
By turning the adjuster "1".
Standard fitting length:
I.D. MARK/
Q'TY
Length
Red/1
Red/2
Red/3
258 mm
(10.16 in)
*252 mm
(9.92 in)
264 mm
(10.39 in)
*258 mm
(10.16 in)
255.5 mm
(10.06 in)
*249.5 mm
(9.82 in)
*For EUROPE
Stiffer Increase the spring pre-
load. (Turn the adjuster "2" in.)
Softer Decrease the spring pre-
load. (Turn the adjuster "2"
out.)
Extent of adjustment:
Maximum Minimum
Position in
which the
spring is turned
in 18 mm (0.71
in) from its free
length
Position in
which the
spring is turned
in 1.5 mm (0.06
in) from its free
length
Locknut:
30 Nm (3.0 m•kg, 22
ft•lb)
Rear frame (upper):
32 Nm (3.2 m•kg, 23
ft•lb)
Rear frame (lower):
29 Nm (2.9 m•kg, 21
ft•lb)
Stiffer "a" Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b" Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position
20 clicks out
(from maximum
position)
Standard position:
10–13 clicks out
* 11–14 clicks out
* For EUROPE
Stiffer "a" Increase the low
compression damping force.
(Turn the adjuster "1" in.)
Softer "b" Decrease the low
compression damping force.
(Turn the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position
20 clicks out
(from maximum
position)
3-16
CHASSIS
STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
(Which align the punch mark "a"
on the adjuster with the punch
mark "b" on the high compression
damping adjuster.)
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
ADJUSTING THE REAR SHOCK
ABSORBER HIGH COMPRESSION
DAMPING FORCE
1. Adjust:
High compression damping force
By turning the adjuster "1".
STANDARD POSITION:
This is the position which is back
by the specific number of turns
from the fully turned-in position.
(Which align the punch mark "a"
on the adjuster with the punch
mark "b" on the adjuster body.)
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
CHECKING THE TIRE PRESSURE
1. Measure:
Tire pressure
Out of specification Adjust.
Check the tire while it is cold.
Loose bead stoppers allow the tire
to slip off its position on the rim
when the tire pressure is low.
A tilted tire valve stem indicates that
the tire slips off its position on the
rim.
If the tire valve stem is found tilted,
the tire is considered to be slipping
off its position. Correct the tire posi-
tion.
CHECKING AND TIGHTENING THE
SPOKES
The following procedure applies to all
of the spokes.
1. Check:
•Spoke
Bend/damage Replace.
Loose spoke Retighten.
Tap the spokes with a screw-
driver.
A tight spoke will emit a clear, ringing
tone; a loose spoke will sound flat.
2. Tighten:
Spoke
(with a spoke nipple wrench "1")
Be sure to retighten these spokes be-
fore and after break-in.
CHECKING THE WHEELS
1. Inspect:
Wheel runout
Elevate the wheel and turn it.
Abnormal runout Replace.
2. Inspect:
Bearing free play
Exist play Replace.
Standard position:
12–15 clicks out
Stiffer "a" Increase the high
compression damping force.
(Turn the adjuster "1" in.)
Softer "b" Decrease the high
compression damping force.
(Turn the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position
2 turns out
(from maximum
position)
Standard position:
1-1/3–1-2/3 turns out
Standard tire pressure:
100 kPa (1.0 kgf/cm
2
,
15 psi)
Spoke nipple wrench:
YM-01521/90890-01521
Spoke:
3 Nm (0.3 m•kg, 2.2
ft•lb)
3-17
CHASSIS
CHECKING AND ADJUSTING THE
STEERING HEAD
1. Place a stand under the engine to
raise the front wheel off the
ground. WARNING! Securely
support the vehicle so that
there is no danger of it falling
over.
2. Check:
Steering stem
Grasp the bottom of the forks and
gently rock the fork assembly
back and forth.
Free play Adjust steering head.
3. Check:
Steering smooth action
Turn the handlebar lock to lock.
Unsmooth action Adjust steer-
ing ring nut.
4. Adjust:
Steering ring nut
Steering ring nut adjustment
steps:
a. Remove the number plate.
b. Remove the handlebar and upper
bracket.
c. Loosen the steering ring nut "1"
using the steering nut wrench "2".
d. Tighten the steering ring nut "3"
using steering nut wrench "4".
Apply the lithium soap base grease
on the thread of the steering stem.
Set the torque wrench to the steer-
ing nut wrench so that they form a
right angle.
e. Loosen the steering ring nut one
turn.
f. Retighten the steering ring nut us-
ing the steering nut wrench.
Avoid over-tightening.
g. Check the steering stem by turn-
ing it lock to lock. If there is any
binding, remove the steering stem
assembly and inspect the steer-
ing bearings.
h. Install the washer "5", upper
bracket "6", washer "7", steering
stem nut "8", handlebar "9", han-
dlebar upper holders "10" and
number plate "11".
The handlebar upper holder should
be installed with the punched mark
"a" forward.
Install the handlebar so that the
marks "b" are in place on both
sides.
Install the handlebar so that the pro-
jection "c" of the handlebar upper
holder is positioned at the mark on
the handlebar as shown.
Insert the end of the fuel breather
hose "12" into the hole in the steer-
ing stem.
First tighten the bolts on the front
side of the handlebar upper holder,
and then tighten the bolts on the
rear side.
Steering nut wrench:
YU-33975/90890-01403
Steering nut wrench:
YU-33975/90890-01403
Steering ring nut (initial
tightening):
38 Nm (3.8 m•kg, 27
ft•lb)
Steering ring nut (final
tightening):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Steering stem nut:
145 Nm (14.5 m•kg, 105
ft•lb)
Handlebar upper holder:
28 Nm (2.8 m•kg, 20
ft•lb)
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Number plate:
7 Nm (0.7 m•kg, 5.1
ft•lb)
3-18
CHASSIS
LUBRICATION
To ensure smooth operation of all
components, lubricate your machine
during setup, after break-in, and after
every race.
1. All control cable
2. Clutch lever pivot
3. Shift pedal pivot
4. Footrest pivot
5. Throttle-to-handlebar contact
6. Drive chain
7. Throttle roller cable guide
8. Throttle roller sliding surface
9. Tube guide cable winding por-
tion
10. Throttle cable end
11. Clutch cable end
A. Use Yamaha cable lube or
equivalent on these areas.
B. Use SAE 10W-40 motor oil or
suitable chain lubricants.
C. Lubricate the following areas
with high quality, lightweight lith-
ium-soap base grease.
Wipe off any excess grease, and
avoid getting grease on the brake
discs.
3-19
ELECTRICAL
ELECTRICAL
CHECKING THE SPARK PLUG
1. Remove:
Spark plug
2. Inspect:
Electrode "1"
Wear/damage Replace.
Insulator color "2"
Normal condition is a medium to
light tan color.
Distinctly different color Check
the engine condition.
When the engine runs for many hours
at low speeds, the spark plug insula-
tor will become sooty, even if the en-
gine and carburetor are in good
operating condition.
3. Measure:
Plug gap "a"
Use a wire gauge or thickness
gauge.
Out of specification Regap.
4. Clean the plug with a spark plug
cleaner if necessary.
5. Tighten:
Spark plug
Before installing a spark plug, clean
the gasket surface and plug sur-
face.
Finger-tighten "a" the spark plug
before torquing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:
•Fuel tank
Refer to "SEAT, FUEL TANK
AND SIDE COVERS" section in
the CHAPTER 4.
Spark plug
Crankcase cover (left)
2. Attach:
Dial gauge "1"
Spark plug hole dial stand "2"
3. Rotate the magneto rotor "1" until
the piston reaches top dead cen-
ter (TDC). When this happens,
the needle on the dial gauge will
stop and reverse directions even
though the rotor is being turned in
the same direction.
4. Set the dial gauge to zero at TDC.
5. From TDC, rotate the rotor clock-
wise until the dial gauge indicates
that the piston is at a specified
distance from TDC.
6. Check:
Ignition timing
Punch mark "a" on rotor should be
aligned with punch mark "b" on
stator.
Not aligned Adjust.
7. Adjust:
Ignition timing
Adjustment steps:
a. Loosen the screws (stator) "1".
b. Align the punch mark on the rotor
with punch mark on the stator "2"
by moving the stator.
c. Tighten the screws (stator).
Spark plug gap "a":
0.6–0.7 mm (0.024–
0.028 in)
Standard spark plug:
BR9EVX/NGK (resistance type)
Spark plug:
20 Nm (2.0 m•kg, 14
ft•lb)
Dial gauge:
YU-3097/90890-01252
Spark plug hole dial
stand:
YU-1256
Ignition timing (B.T.D.C.):
0.48 mm (0.019 in)
Screw (stator):
7 Nm (0.7 m•kg, 5.1
ft•lb)
4-1
SEAT, FUEL TANK AND SIDE COVERS
ENGINE
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
SEAT, FUEL TANK AND SIDE COVERS
REMOVING THE SEAT, FUEL TANK AND SIDE COVERS
Order Part name Q'ty Remarks
Turn the fuel cock to "OFF".
Disconnect the fuel hose.
1Seat 1
2 Air scoop (left and right) 2
3 Fitting band 1 Remove on fuel tank side.
4 Bolt (fuel tank) 2
5 Fuel tank 1
6 Left side cover 1 Refer to removal section.
7 Right side cover 1 Refer to removal section.
8 Number plate 1 Refer to removal section.
19 Nm (1.9 m kg, 13 ft lb)
7 Nm (0.7 m kg, 5.1 ft lb)
7 Nm (0.7 m kg, 5.1 ft lb)
7 Nm (0.7 m kg, 5.1 ft lb)
7 Nm (0.7 m kg, 5.1 ft lb)
7 Nm (0.7 m kg, 5.1 ft lb)
7 Nm (0.7 m kg, 5.1 ft lb)
7 Nm (0.7 m kg, 5.1 ft lb)
19 Nm (1.9 m kg, 13 ft lb)
6 Nm (0.6 m kg, 4.3 ft lb)
6 Nm (0.6 m kg, 4.3 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
4 Nm (0.4 m kg, 2.9 ft lb)
4
4-2
SEAT, FUEL TANK AND SIDE COVERS
REMOVING THE SIDE COVER
1. Remove:
Bolt (side cover)
Side cover (left and right) "1"
Draw the side cover downward to re-
move it because its claws "a" are in-
serted in the air filter case.
REMOVING THE NUMBER PLATE
1. Remove:
Bolt (number plate)
Number plate "1"
The projection "a" is inserted into
the band of the number plate. Pull
the band off the projection before
removal.
Remove the clutch cable "2" from
the cable guide "b" on the number
plate.
The projection "c" on the lower
bracket is inserted into the number
plate. Remove the number plate by
pulling it off the projection.
4-3
EXHAUST PIPE AND SILENCER
EXHAUST PIPE AND SILENCER
REMOVING THE EXHAUST PIPE AND SILENCER
Order Part name Q'ty Remarks
Right side cover
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
1 Bolt (silencer) 2
2 Washer [ø=26 mm (1.02 in)] 1
3 Washer [ø=22 mm (0.87 in)] 1
4 Silencer 1
5 Collar [L=15.5 mm (0.61 in)] 1
6 Collar [L=13.5 mm (0.53 in)] 1
7 Grommet (front) 1
8 Grommet (rear) 1
9 Tension spring 2
10 Bolt (exhaust pipe) 2
11 Exhaust pipe 1
10 Nm (1.0 m kg, 7.2 ft lb)
12 Nm (1.2 m kg, 8.7 ft lb)
12 Nm (1.2 m kg, 8.7 ft lb)
12 Nm (1.2 m kg, 8.7 ft lb)
12 Nm (1.2 m kg, 8.7 ft lb)
4-4
EXHAUST PIPE AND SILENCER
CHANGING THE SILENCER FIBER
1. Remove:
Side cover (right)
Bolt (silencer) "1"
Silencer "2"
Bolt (fiber) "3"
2. Remove:
Inner pipe "1"
3. Replace:
Fiber "2"
4. Install:
Inner pipe
Fully apply Quick gasket
®
(Yamaha
bond No.1215) or equivalent as
shown.
5. Install:
Bolt (fiber) "1"
Silencer "2"
Bolt [silencer (front)] "3"
Bolt [silencer (rear)] "4"
Side cover (right)
Yamaha bond No.1215
(Three Bond
®
No.1215):
90890-85505
Bolt (fiber):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt [silencer (front)] :
12 Nm (1.2 m•kg, 8.7
ft•lb)
Bolt [silencer (rear)] :
12 Nm (1.2 m•kg, 8.7
ft•lb)
Side cover (right):
7 Nm (0.7 m•kg, 5.1
ft•lb)
4-5
RADIATOR
RADIATOR
REMOVING THE RADIATOR
Order Part name Q'ty Remarks
Drain the coolant.
Refer to "CHANGING THE COOLANT" sec-
tion in the CHAPTER 3.
Seat and fuel tank
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
1 Radiator guard 2
2 Radiator hose clamp (radiator hose 1, 3) 2 Only loosening.
3 Radiator hose 2 1
4 Left radiator 1
5 Radiator hose 4 1
6 Right radiator 1
7 Radiator hose 1 1
8 Radiator hose 3 1
9 Radiator breather hose 1
10 Nm (1.0 m kg, 7.2 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
4-6
RADIATOR
HANDLING NOTE
Do not remove the radiator cap
when the engine and radiator are
hot. Scalding hot fluid and steam
may be blown out under pressure,
which could cause serious injury.
When the engine has cooled, open
the radiator cap by the following
procedure:
Place a thick rag, like a towel, over
the radiator cap, slowly rotate the
cap counterclockwise to the de-
tent. This procedure allows any re-
sidual pressure to escape. When
the hissing sound has stopped,
press down on the cap while turn-
ing counterclockwise and remove
it.
CHECKING THE RADIATOR
1. Inspect:
Radiator core "1"
Obstruction Blow out with com-
pressed air through rear of the ra-
diator.
Bent fin Repair/replace.
INSTALLING THE RADIATOR
1. Install:
Radiator breather hose "1"
Radiator hose 3 "2"
Radiator hose 1 "3"
To right radiator "4".
Clamp the radiator hose in the direc-
tion as shown.
2. Install:
Right radiator "1"
Washer "2"
Bolt (right radiator) "3"
Radiator hose 4 "4"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
3. Install:
Left radiator "1"
Washer "2"
Bolt (left radiator) "3"
Radiator hose 2 "4"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
4. Tighten:
Radiator hose clamp 1, 3 "5"
5. Install:
Radiator guard "1"
Bolt (radiator guard) "2"
Fit the hook "a" on the inner side first
into the radiator.
Radiator hose 3:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Radiator hose 1:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (right radiator):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Radiator hose 4:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (left radiator):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Radiator hose 2:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Radiator hose clamp 1, 3:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (radiator guard):
10 Nm (1.0 m•kg, 7.2
ft•lb)
4-7
CARBURETOR AND REED VALVE
CARBURETOR AND REED VALVE
REMOVING THE CARBURETOR AND REED VALVE
Order Part name Q'ty Remarks
Fuel tank
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
1 Clamp (carburetor joint) 2 Loosen the screw (carburetor joint).
2 Carburetor 1
3 Carburetor joint 1
4 Reed valve assembly 1
5 Stopper (reed valve) 2
6 Reed valve 2
10 Nm (1.0 m kg, 7.2 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
1 Nm (0.1 m kg, 0.7 ft lb)
4-8
CARBURETOR AND REED VALVE
DISASSEMBLING THE CARBURETOR
Order Part name Q'ty Remarks
1 Mixing chamber top 1 Refer to removal section.
2 Throttle valve 1
3 Needle holder 1
4 Jet needle 1
5 Float chamber 1
6 Needle jet cover 1
7 Float pin 1
8 Float 1
9 Valve seat 1
10 Main jet 1
11 Main jet holder 1
12 Pilot jet 1
13 Starter plunger 1
14 Throttle stop screw 1
15 Pilot air screw 1
4 Nm (0.4 m kg, 2.9 ft lb)
4-9
CARBURETOR AND REED VALVE
HANDLING NOTE
Do not disassemble the venturi
block "1" and main nozzle "2" be-
cause it will cause a drop in carbu-
retor performance.
REMOVING THE THROTTLE
VALVE
1. Remove:
Throttle valve "1"
Ring "2"
Spring (throttle valve) "3"
Mixing chamber top "4"
Throttle cable "5"
While compressing the spring (throt-
tle valve), disconnect the throttle ca-
ble.
CHECKING THE CARBURETOR
1. Inspect:
Carburetor body
Contamination Clean.
When cleaning the main air pas-
sage "a", do not blow air at the fil-
ter side because it will clog the
passage with mud or sand.
Use a petroleum based solvent for
cleaning. Blow out all passages and
jets with compressed air.
Never use a wire.
When cleaning the main air pas-
sage, blow air through it while cov-
ering the nozzle with a clean rag.
2. Inspect:
•Main jet "1"
Main jet holder "2"
Pilot jet "3"
Contamination Clean.
Use a petroleum based solvent for
cleaning. Blow out all passages and
jets with compressed air.
Never use a wire.
CHECKING THE NEEDLE VALVE
1. Inspect:
Needle valve "1"
Valve seat "2"
Grooved wear "a" Replace.
Dust "b" Clean.
Always replace the needle valve and
valve seat as a set.
CHECKING THE THROTTLE
VALVE
1. Check:
Free movement
Stick Repair or replace.
Insert the throttle valve "1" into the
carburetor body, and check for free
movement.
CHECKING THE JET NEEDLE
1. Inspect:
Jet needle "1"
Bends/wear Replace.
Clip groove
Free play exists/wear Replace.
Clip position
CHECKING THE FILTER
1. Inspect:
•Filter "1"
Damage Replace.
Inspect the filter as it is assembled to
the carburetor. Do not remove the fil-
ter except when replacing it.
MEASURING AND ADJUSTING
THE FUEL LEVEL
1. Measure:
Fuel level "a"
Out of specification Adjust.
Fuel level Measurement and ad-
justment steps:
a. Remove the drain plug.
b. Connect the fuel level gauge
adapter "2" and fuel level gauge
"1" to the float chamber.
c. Hold the fuel level gauge vertical-
ly next to the float chamber mat-
ing surface.
Standard clip position:
No.3 Groove
Fuel level "a":
9.5–10.5 mm (0.37–0.41
in)
Above the float cham-
ber mating surface
Fuel level gauge adapter:
YM-01470/90890-01470
Fuel level gauge:
YM-1312-A/90890-
01312
4-10
CARBURETOR AND REED VALVE
d. Measure the fuel level with the
fuel level gauge.
Keep the carburetor and fuel level
gauge vertically when measuring the
fuel level.
e. If the fuel level is not within speci-
fication, inspect the valve seat
and needle valve.
f. If either is worn, replace them
both.
g. If both are fine, adjust the fuel lev-
el by bending the float tab "b" on
the float.
h. Recheck the fuel level.
CHECKING THE FLOAT
1. Inspect:
Float "1"
Damage Replace.
CHECKING THE REED VALVE
1. Measure:
Reed valve bending "a"
Out of specification Replace.
2. Measure:
Valve stopper height "a"
Out of specification Adjust
stopper/Replace valve stopper.
INSTALLING THE REED VALVE
1. Install:
Reed valve "1"
Stopper (reed valve) "2"
Screw (reed valve) "3"
Install the reed valve with the reed
valve bending as shown.
Note the cut "a" in the lower corner
of the reed and stopper plate.
Tighten each screw gradually to
avoid warping.
2. Install:
Reed valve assembly "1"
Reed valve spacer "2"
3. Install:
Carburetor joint "1"
Bolt (carburetor joint) "2"
ASSEMBLING THE CARBURETOR
1. Install:
Throttle stop screw "1"
Locknut "2"
Pilot air screw "3"
Note the following installation
points:
a. Screw in the pilot air screw until it
is lightly seated.
b. Back out it by the specified num-
ber of turns.
2. Install:
Starter plunger "1"
3. Install:
Main jet holder "1"
•Main jet "2"
Pilot jet "3"
Valve seat "4"
Screw (valve seat) "5"
4. Install:
Needle valve "1"
Float "2"
Float pin "3"
Screw (float pin) "4"
Needle jet cover "5"
Reed valve bending limit
"a":
0.2 mm (0.008 in)
Valve stopper height "a":
8.2–8.6 mm (0.323–
0.339 in)
Screw (reed valve):
1 Nm (0.1 m•kg, 0.7
ft•lb)
Bolt (carburetor joint):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Pilot air screw:
2-1/4 turns out
4-11
CARBURETOR AND REED VALVE
After installing the needle valve to
the float, install them to the carbure-
tor.
Check the float for smooth move-
ment.
5. Install:
Float chamber "1"
Plate "2"
Screw (float chamber) "3"
6. Install:
Jet needle "1"
Needle holder "2"
To throttle valve "3".
7. Install:
Throttle cable "1"
Locknut "2"
Mixing chamber top "3"
Spring (throttle valve) "4"
Ring "5"
Throttle valve "6"
While compressing the spring, con-
nect the throttle cable.
Align the projection "a" on the ring
with the groove "b" in the needle
holder "7".
8. Install:
Mixing chamber top "1"
Screw (mixing chamber top) "2"
To carburetor "3".
After installing, check the throttle grip
for smooth movement.
9. Install:
Air vent hose "1"
Overflow hose "2"
•Clamp "3"
Pass the air vent hose at the rear (on
the air cleaner side) of the throttle ca-
ble "4".
INSTALLING THE CARBURETOR
1. Install:
Carburetor "1"
Install the projection between the car-
buretor joint slots.
2. Tighten:
Bolt (air filter joint) "1"
Bolt (carburetor joint) "2"
3. Clamp:
Air vent hose "1"
Overflow hose "2"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
4. Adjust:
Idle speed
Refer to "ADJUSTING THE EN-
GINE IDLING SPEED" section in
the CHAPTER 3.
Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Bolt (air filter joint):
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (carburetor joint):
2 Nm (0.2 m•kg, 1.4
ft•lb)
4-12
CYLINDER HEAD, CYLINDER AND PISTON
CYLINDER HEAD, CYLINDER AND PISTON
REMOVING THE CYLINDER HEAD AND CYLINDER
Order Part name Q'ty Remarks
Seat and fuel tank
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
Exhaust pipe and silencer
Refer to "EXHAUST PIPE AND SILENCER"
section.
Radiator Refer to "RADIATOR" section.
1 Spark plug 1
2 Engine bracket 2
3 Nut (cylinder head) 5
Loosen each nut 1/4 turn, and remove them
after all nuts are loosened.
4 Cylinder head 1
5 Power valve housing 1
6 Push rod 1 Refer to removal section.
7 Nut (cylinder) 4
8 Cylinder 1
5 Nm (0.5 m kg, 3.6 ft lb)
4 Nm (0.4 m kg, 2.9 ft lb)
13 Nm (1.3 m kg, 9.4 ft lb)
28 Nm (2.8 m kg, 20 ft lb)
20 Nm (2.0 m kg, 14 ft lb)
30 Nm (3.0 m kg, 22 ft lb)
34 Nm (3.4 m kg, 24 ft lb)
4-13
CYLINDER HEAD, CYLINDER AND PISTON
REMOVING THE PISTON AND POWER VALVE
Order Part name Q'ty Remarks
1 Piston pin clip 2 Refer to removal section.
2 Piston pin 1 Refer to removal section.
3 Piston 1 Refer to removal section.
4 Small end bearing 1 Refer to removal section.
5 Piston ring 1 Refer to removal section.
6 Power valve cover 1
7 Thrust plate 1
8 Bolt (link lever) 1
9 Valve holder 1
10 Valve shaft 1
11 Collar 2
12 Link lever 1
13 Spring 2
14 Power valve 1 1
15 Power valve 2 1
4 Nm (0.4 m kg, 2.9 ft lb)
4 Nm (0.4 m kg, 2.9 ft lb)
8 Nm (0.8 m kg, 5.8 ft lb)
5 Nm (0.5 m kg, 3.6 ft lb)
4-14
CYLINDER HEAD, CYLINDER AND PISTON
REMOVING THE PUSH ROD
1. Remove:
Bolt (push rod) "1"
Push rod "2"
Set the collar "3" included in owner's
tool kit to remove the bolt (push rod).
REMOVING THE PISTON AND
PISTON RING
1. Remove:
Piston pin clip "1"
Before removing the piston pin clip,
cover the crankcase with a clean rag
to prevent the piston pin clip from fall-
ing into the crankcase cavity.
2. Remove:
Piston pin "1"
Piston "2"
Small end bearing "3"
Before removing each piston pin, de-
burr the clip groove and pin hole area.
If the piston pin groove is deburred
and the piston pin is still difficult to re-
move, use the piston pin puller set
"4".
Do not use a hammer to drive the
piston pin out.
3. Remove:
Piston ring "1"
Take care not to scratch the piston or
damage the piston ring by expanding
it more than necessary.
CHECKING THE CYLINDER HEAD
1. Eliminate:
Carbon deposits
Use a rounded scraper "1".
Take care to avoid damaging the
spark plug threads. Do not use a
sharp instrument. Avoid scratching
the aluminum.
2. Inspect:
Cylinder head water jacket
Crust of minerals/Rust Re-
place.
3. Measure:
Cylinder head warpage
Out of specification Resurface.
Warpage measurement and resur-
facing steps:
a. Attach a straightedge "1" and a
thickness gauge "2" on the cylin-
der head.
b. Measure the warpage.
c. If the warpage is out of specifica-
tion, resurface the cylinder head.
d. Place a 400–600 grit wet sandpa-
per "3" on the surface plate, and
resurface the head "4" using a fig-
ure-eight sanding pattern.
To ensure an even surface rotate the
cylinder head several times.
CHECKING THE CYLINDER
1. Eliminate:
Carbon deposits
Use a rounded scraper "1".
Do not use a sharp instrument. Avoid
scratching the aluminum.
2. Inspect:
Cylinder inner surface
Score marks Repair or replace.
Use #400–600 grit wet sandpa-
per.
Do not rebore the cylinder.
3. Measure:
Cylinder bore "C"
Use cylinder gauge "1".
Out of specification Replace.
Measure the cylinder bore "C" in par-
allel (A, B, C) to and at right angles to
the crankshaft (a, b). Then, find the
average of the measurements.
Piston pin puller set:
YU-1304/90890-01304
Cylinder head warpage:
Less than 0.03 mm
(0.0012 in)
4-15
CYLINDER HEAD, CYLINDER AND PISTON
CHECKING THE PISTON
1. Eliminate:
Carbon deposits
From the piston crown "a" and
ring groove "b".
2. Inspect:
Piston wall
Score marks Repair or replace.
3. Measure:
Piston skirt diameter
Use micrometer "1".
Measure the specific distance "a"
from the bottom edge.
Out of specification Replace.
CHECKING THE PISTON PIN AND
SMALL END BEARING
1. Inspect:
Piston pin
Small end bearing
Signs of heat discoloration Re-
place.
2. Measure:
Piston pin outside diameter
Use micrometer "1".
Out of specification Replace.
3. Check:
Free play (when the piston pin "1"
is in place in the piston "2")
There should be no noticeable for
the play.
Free play exists Replace pis-
ton pin and/or piston.
4. Install:
Small end bearing
Piston pin
Into the small end of connecting
rod.
5. Check:
Free play
There should be no noticeable
free play.
Free play exists Inspect the
connecting rod for wear/Replace
the pin and/or connecting rod as
required.
CHECKING THE PISTON RING
1. Install:
Piston ring
Into the cylinder.
Push the ring with the piston
crown.
2. Measure:
End gap
Use a thickness gauge "1".
Out of specification Replace.
3. Measure:
Side clearance
Use a thickness gauge "1".
Out of specification Replace
piston and/or ring.
Check at several points.
Standard Wear limit
Cylin-
der bore
"C"
54.000–
54.014 mm
(2.1260–
2.1265 in)
54.1 mm
(2.130 in)
Taper
"T"
0.05 mm
(0.0020 in)
"C" = Maximum Aa–Cb
"T" = (Maximum Aa, or Ab) - (Max-
imum Ba, or Bb)
Distance
"a"
Piston diame-
ter
17.5 mm
(0.69 in)
53.957–53.972
mm (2.1243–
2.1249 in)
Piston pin outside diam-
eter:
Standard <Limit>
14.995–15.000
mm (0.5904–
0.5906 in)
14.975 mm
(0.5896 in)
Ring end gap (installed):
Standard <Limit>
0.5–0.7 mm
(0.020–0.028 in)
1.2 mm (0.047
in)
Side clearance:
Standard <Limit>
0.035–0.070
mm (0.0014–
0.0028 in)
0.1 mm (0.004
in)
4-16
CYLINDER HEAD, CYLINDER AND PISTON
CHECKING THE PISTON
CLEARANCE
1. Calculate:
Piston clearance
Out of specification Replace
piston, and piston ring and/or cyl-
inder.
Refer to "Cylinder" and "Piston".
CHECKING THE COMBINATION
OF PISTON AND CYLINDER
1. Check:
Cylinder mark "a"
2. Check:
Piston mark "a"
3. Combination:
Combine the piston and cylinder
by the following chart.
When you purchase a cylinder, you
cannot designate its size. Choose the
piston that matches the above chart.
CHECKING THE POWER VALVE
1. Inspect:
Power valve 1,2 "1"
Wear/Damage Replace.
Carbon deposits Remove.
Valve holder "2"
Link lever "3"
Valve shaft "4"
•Collar "5"
Wear/Damage Replace.
Spring "6"
Broken Replace.
CHECKING THE POWER VALVE
HOLE ON CYLINDER
1. Remove:
Carbon deposits
From power valve hole surface
"a".
Do not use a sharp instrument. Avoid
scratching the aluminum.
INSTALLING THE POWER VALVE
1. Install:
Power valve 1 "1"
Power valve 2 "2"
Bolt (power valve) "3"
Install the power valve at cut-away
faced "a" for down side.
2. Install:
Spring "1"
Link lever "2"
•Collar "3"
Valve shaft "4"
Valve holder "5"
Bolt (link lever) "6"
PISTON CLEARANCE = CYLIN-
DER BORE - PISTON DIAME-
TER
Piston clearance:
Standard <Limit>
0.040–0.045
mm (0.0016–
0.0018 in)
0.1 mm (0.004
in)
Cylinder mark
"a"
Cylinder size
A
54.000–54.002
mm (2.1260–
2.1261 in)
B
54.004–54.006
mm (2.1261–
2.1262 in)
C
54.008–54.010
mm (2.1263–
2.1264 in)
D
54.012–54.014
mm (2.1265–
2.1265 in)
Piston mark "a"
(color)
Piston size
A (red)
53.957–53.960
mm
(2.1243–2.1244
in)
B (orange)
53.961–53.964
mm
(2.1244–2.1246
in)
C (green)
53.965–53.968
mm
(2.1246–2.1247
in)
D (purple)
53.969–53.972
mm
(2.1248–2.1249
in)
Cylinder mark
Piston mark
(color)
AA (red)
BB (orange)
CC (green)
D D (purple)
Bolt (power valve):
8 Nm (0.8 m•kg, 5.8
ft•lb)
Bolt (link lever):
4 Nm (0.4 m•kg, 2.9
ft•lb)
4-17
CYLINDER HEAD, CYLINDER AND PISTON
Install the spring to the link lever,
and then to the cylinder.
Install the spring with its stopper
portion "a" facing inward.
Apply the lithium soap base grease
on the oil seal lip.
3. Install:
Thrust plate "1"
Screw (thrust plate) "2"
4. Check:
Power valve smooth movement
Unsmooth movement Repair
or replace.
5. Install:
Gasket (power valve cover) "1"
Power valve cover "2"
Screw (power valve cover) "3"
YPVS breather hose "4"
Install the power valve cover so that
the arrow mark "a" faces upward.
Install the clamp of the YPVS
breather hose with its opening por-
tion "b" facing backward.
INSTALLING THE PISTON RING
AND PISTON
1. Install:
Piston ring "1"
Take care not to scratch the piston
or damage the piston ring.
Align the piston ring gap with the pin
"2".
After installing the piston ring,
check the smooth movement of it.
2. Install:
Gasket (cylinder) "1"
Small end bearing "2"
Dowel pin "3"
Apply the engine oil onto the bear-
ing (crankshaft and connecting rod)
and connecting rod big end wash-
ers.
Install the gasket with the seal print
side toward the crankcase.
3. Install:
•Piston "1"
Piston pin "2"
Piston pin clip "3"
The arrow "a" on the piston dome
must point to exhaust side.
Before installing the piston pin clip,
cover the crankcase with a clean
rag to prevent the piston pin clip
from falling into the crankcase cavi-
ty.
When installing the piston pin
clip, use the hand so that it may
not be distorted.
Do not allow the clip open ends
to meet the piston pin slot "b".
INSTALLING THE CYLINDER
HEAD AND CYLINDER
1. Apply:
Engine oil
To piston "1", piston ring "2" and
cylinder surface.
2. Install:
Cylinder "1"
Make sure the piston ring is prop-
erly positioned. Install the cylinder
with one hand while compressing
the piston ring with the other hand.
After installing, check the smooth
movement of the piston.
Screw (thrust plate):
4 Nm (0.4 m•kg, 2.9
ft•lb)
Screw (power valve cov-
er):
5 Nm (0.5 m•kg, 3.6
ft•lb)
4-18
CYLINDER HEAD, CYLINDER AND PISTON
3. Install:
Nut (cylinder) "1"
Tighten the nuts in stage, using a
crisscross pattern.
4. Install:
•Collar "1"
Push rod "2"
Plain washer "3"
Bolt (push rod) "4"
Set the collar "5" included in own-
er's tool kit to install the bolt (push
rod).
Do not forget to remove the collar.
5. Install:
Gasket (power valve housing)
Power valve housing "1"
Bolt (power valve housing) "2"
6. Install:
O-ring "1"
Apply the lithium soap base grease
on the O-rings.
7. Install:
Cylinder head "1"
Copper washer "2"
Nut (cylinder head) "3"
Tighten the nuts (cylinder head) in
stage, using a crisscross pattern.
8. Install:
Engine bracket "1"
Bolt (engine bracket) "2"
Engine mounting bolt (upper) "3"
9. Install:
Spark plug "1"
Spark plug cap "2"
Nut (cylinder):
30 Nm (3.0 m•kg, 22
ft•lb)
Bolt (push rod):
5 Nm (0.5 m•kg, 3.6
ft•lb)
Bolt (power valve hous-
ing):
4 Nm (0.4 m•kg, 2.9
ft•lb)
Nut (cylinder head):
28 Nm (2.8 m•kg, 20
ft•lb)
Bolt (engine bracket):
34 Nm (3.4 m•kg, 24
ft•lb)
Engine mounting bolt
(upper):
34 Nm (3.4 m•kg, 24
ft•lb)
Spark plug:
20 Nm (2.0 m•kg, 14
ft•lb)
4-19
CLUTCH
CLUTCH
REMOVING THE CLUTCH
Order Part name Q'ty Remarks
Drain the transmission oil.
Refer to "CHANGING THE TRANSMISSION
OIL" section in the CHAPTER 3.
Bolt (brake pedal) Shift the brake pedal downward.
Rotor and stator Refer to "CDI MAGNETO" section.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Bolt (clutch spring) 5
3 Clutch spring 5
4 Pressure plate 1
5 Friction plate 8
6 Clutch plate 7
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
4-20
CLUTCH
REMOVING THE CLUTCH BOSS
Order Part name Q'ty Remarks
1 Push rod 1 1
2 Circlip 1
3 Washer 1
4 Bearing 1
5Ball 1
6 Push rod 2 1
7 Nut (clutch boss) 1 Refer to removal section.
8 Lock washer 1 Refer to removal section.
9 Clutch boss 1 Refer to removal section.
10 Thrust washer [D=ø34 mm (1.34 in)] 1
11 Primary driven gear 1
12 Bearing 1
13 Thrust washer [D=ø34 mm (1.34 in)] 1
14 Push lever shaft 1
80
Nm
(8.0
m
kg,
58
ft
lb)
4-21
CLUTCH
REMOVING THE CLUTCH BOSS
1. Remove:
•Nut "1"
Lock washer "2"
Clutch boss "3"
Straighten the lock washer tab and
use the clutch holding tool "4" to hold
the clutch boss.
A. For USA and CDN
B. Except for USA and CDN
CHECKING THE CLUTCH
HOUSING AND BOSS
1. Inspect:
Clutch housing "1"
Cracks/wear/damage Replace.
Clutch boss "2"
Scoring/wear/damage Re-
place.
CHECKING THE PRIMARY DRIVEN
GEAR
1. Check:
Circumferential play
Free play exists Replace.
Gear teeth "a"
Wear/damage Replace.
CHECKING THE CLUTCH
SPRINGS
1. Measure:
Clutch spring free length "a"
Out of specification Replace
springs as a set.
CHECKING THE FRICTION
PLATES
1. Measure:
Friction plate thickness
Out of specification Replace
friction plate as a set.
Measure at all four points.
CHECKING THE CLUTCH PLATES
1. Measure:
Clutch plate warpage
Out of specification Replace
clutch plate as a set.
Use a surface plate "1" and thick-
ness gauge "2".
CHECKING THE PUSH LEVER
SHAFT
1. Inspect:
Push lever shaft "1"
Wear/Damage Replace.
CHECKING THE PUSH ROD
1. Inspect:
Push rod 1 "1"
Bearing "2"
Washer "3"
Push rod 2 "4"
•Ball "5"
Wear/damage/bend Replace.
INSTALLING THE PUSH LEVER
SHAFT
1. Install:
Push lever shaft "1"
Apply the lithium soap base grease
on the oil seal lip and push lever
shaft.
INSTALLING THE CLUTCH
1. Install:
Thrust washer [D=ø34 mm (1.34
in)] "1"
Spacer "2"
Bearing "3"
Primary driven gear "4"
Apply the transmission oil on the
bearing, spacer and primary driven
gear inner circumference.
Clutch holding tool:
YM-91042/90890-04086
Clutch spring free length
"a":
40.1 mm (1.579 in)
<Limit>: 38.1 mm
(1.500 in)
Friction plate thickness:
2.9–3.1 mm (0.114–
0.122 in)
<Limit>: 2.8 mm (0.110
in)
Warp limit:
0.2 mm (0.008 in)
4-22
CLUTCH
2. Install:
Thrust washer [D=ø34 mm (1.34
in)] "1"
Clutch boss "2"
3. Install:
Lock washer "1"
Nut (clutch boss) "2"
Use the clutch holding tool "3" to hold
the clutch boss.
A. For USA and CDN
B. Except for USA and CDN
4. Bend the lock washer "1" tab.
5. Install:
Friction plate "1"
Clutch plate "2"
Install the clutch plates and friction
plates alternately on the clutch
boss, starting with a friction plate
and ending with a friction plate.
Apply the transmission oil on the
friction plates and clutch plates.
6. Install:
•Bearing "1"
Washer "2"
Circlip "3"
To push rod 1 "4".
Apply the lithium soap base grease
on the bearing and washer.
7. Install:
Push rod 2 "1"
Ball "2"
Push rod 1 "3"
Apply the transmission oil on the
push rod 1, 2 and ball.
8. Install:
Pressure plate "1"
9. Install:
Clutch spring "1"
Bolt (clutch spring) "2"
Tighten the bolts in stage, using a
crisscross pattern.
10. Install:
Dowel pin "1"
Gasket (clutch cover) "2"
11. Install:
Clutch cover "1"
Bolt (clutch cover) "2"
Tighten the bolts in stage, using a
crisscross pattern.
12. Install:
O-ring "1"
Clutch cable "2"
Apply the lithium soap base grease
on the O-ring.
Nut (clutch boss):
80 Nm (8.0 m•kg, 58
ft•lb)
Clutch holding tool:
YM-91042/90890-04086
Bolt (clutch spring):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (clutch cover):
10 Nm (1.0 m•kg, 7.2
ft•lb)
4-23
KICK SHAFT AND SHIFT SHAFT
KICK SHAFT AND SHIFT SHAFT
REMOVING THE PRIMARY DRIVE GEAR
Order Part name Q'ty Remarks
Drain the transmission oil.
Refer to "CHANGING THE TRANSMISSION
OIL" section in the CHAPTER 3.
Clutch cable Disconnect at engine side.
Bolt (brake pedal) Shift the brake pedal downward.
Radiator hose 4 Disconnect at water pump side.
Bolt (push rod)
Refer to "CYLINDER HEAD, CYLINDER
AND PISTON" section.
1 Kickstarter crank 1
2 Crankcase cover (right) 1
3 Bolt (Primary drive gear) 1 Only loosening. Refer to removal section.
4 Primary driven gear 1 Refer to "CLUTCH" section.
5 Primary drive gear 1
4-24
KICK SHAFT AND SHIFT SHAFT
REMOVING THE KICK SHAFT AND SHIFT SHAFT
Order Part name Q'ty Remarks
1 Kick idle gear 1
2 Kick shaft assembly 1 Refer to removal section.
3 Shift pedal 1
4 Shift shaft 1
5 Roller 1
6 Shift guide 1 Refer to removal section.
7 Shift lever assembly 1 Refer to removal section.
8 Stopper lever 1
4-25
KICK SHAFT AND SHIFT SHAFT
REMOVING THE PRIMARY DRIVE
GEAR
1. Loosen:
Bolt (primary drive gear) "1"
Place an aluminum plate "a" between
the teeth of the primary drive gear "2"
and driven gear "3".
REMOVING THE KICK SHAFT
ASSEMBLY
1. Remove:
Kick shaft assembly "1"
Unhook the torsion spring "2" from
the hole "a" in the crankcase.
REMOVING THE SHIFT GUIDE
AND SHIFT LEVER ASSEMBLY
1. Remove:
Bolt (shift guide)
Shift guide "1"
Shift lever assembly "2"
The shift lever assembly is disassem-
bled at the same time as the shift
guide.
REMOVING THE SEGMENT
1. Remove:
Bolt (segment) "1"
Segment "2"
Turn the segment counterclockwise
until it stops and loosen the bolt.
If the segment gets an impact, it
may be damaged. Take care not to
give an impact to the segment
when removing the bolt.
CHECKING THE KICK SHAFT AND
KICK GEAR
1. Check:
Kick gear smooth movement
Unsmooth movement Replace.
2. Inspect:
Kick shaft "1"
Wear/damage Replace.
CHECKING THE KICK GEAR AND
KICK IDLE GEAR
1. Inspect:
Kick gear "1"
Kick idle gear "2"
Gear teeth "a"
Wear/damage Replace.
CHECKING THE KICK GEAR CLIP
1. Measure:
Kick clip friction force
Out of specification Replace.
Use a spring gauge "1".
CHECKING THE SHIFT SHAFT
1. Inspect:
Shift shaft "1"
Bend/damage Replace.
Spring "2"
Broken Replace.
CHECKING THE SHIFT GUIDE AND
SHIFT LEVER ASSEMBLY
1. Inspect:
Shift guide "1"
Shift lever "2"
•Pawl "3"
Pawl pin "4"
Spring "5"
Wear/damage Replace.
CHECKING THE STOPPER LEVER
1. Inspect:
Stopper lever "1"
Wear/damage Replace.
•Roller "2"
Rotate outer race with a finger.
Rough spot/Seizure Replace
the stopper lever.
Torsion spring "3"
Broken Replace.
CHECKING THE PRIMARY DRIVE
GEAR AND PRIMARY DRIVEN
GEAR
1. Inspect:
Primary drive gear "1"
Primary driven gear "2"
Wear/Damage Replace.
Kick clip friction force:
0.8–1.2 kg (1.8–2.6 lb)
4-26
KICK SHAFT AND SHIFT SHAFT
INSTALLING THE SEGMENT
1. Install:
Segment "1"
Bolt (segment)
Align the notch "a" on the segment
with the pin "b" on the shift cam.
If the segment gets an impact, it
may be damaged. Take care not to
give an impact to the segment
when tightening the bolt.
INSTALLING THE STOPPER
LEVER
1. Install:
Torsion spring "1"
Stopper lever "2"
Bolt (stopper lever) "3"
•Align the stopper lever roller with the
slot on segment.
•When installing the stopper lever,
make sure that the torsion spring is
in the position as shown.
INSTALLING THE SHIFT GUIDE
AND SHIFT LEVER ASSEMBLY
1. Install:
Spring "1"
Pawl pin "2"
Pawl "3"
To shift lever "4".
2. Install:
Shift lever assembly "1"
To shift guide "2".
3. Install:
Shift lever assembly "1"
Shift guide "2"
The shift lever assembly is installed
at the same time as the shift guide.
Apply the transmission oil on the
bolt (segment) shaft.
4. Install:
Bolt (shift guide) "1"
INSTALLING THE SHIFT SHAFT
1. Install:
•Roller "1"
Shift shaft "2"
Apply the transmission oil on the roll-
er and shift shaft.
INSTALLING THE KICK SHAFT
ASSEMBLY
1. Install:
Kick gear "1"
Washer "2"
Torsion spring "3"
To kick shaft "4".
Make sure the stopper "a" of the tor-
sion spring fits into the hole "b" on the
kick shaft.
2. Install:
Spring guide "1"
Slide the spring guide into the kick
shaft, make sure the groove "a" in the
spring guide fits on the stopper of the
torsion spring.
Bolt (segment):
30 Nm (3.0 m•kg, 22
ft•lb)
Bolt (stopper lever):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (shift guide):
10 Nm (1.0 m•kg, 7.2
ft•lb)
4-27
KICK SHAFT AND SHIFT SHAFT
3. Install:
Kick shaft assembly "1"
Apply the transmission oil on the
kick shaft.
Slide the kick shaft assembly into
the crankcase, make sure the clip
"2" and kick shaft stopper "a" fit into
their home position "b", "c".
4. Hook:
Torsion spring "1"
Turn the torsion spring clockwise and
hook into the proper hole "a" in the
crankcase.
INSTALLING THE KICK IDLE
GEAR
1. Install:
Kick idle gear "1"
Washer "2"
Circlip "3"
Apply the transmission oil on the kick
idle gear inner circumference.
INSTALLING THE PRIMARY DRIVE
GEAR
1. Install:
Spacer "1"
Primary drive gear "2"
•Bolt "3"
Install the primary drive gear with its
depressed side toward you.
2. Install:
Primary driven gear
Refer to "CLUTCH" section.
3. Tighten:
Bolt (primary drive gear) "1"
Place an aluminum plate "a" between
the teeth of the primary drive gear
and driven gear.
4. Install:
Dowel pin "1"
Gasket [crankcase cover (right)]
"2"
5. Install:
Crankcase cover (right) "1"
Mesh the governor gear "2", and im-
peller shaft gear "3" with primary
drive gear "4".
6. Install:
Bolt [crankcase cover (right)] "1"
Tighten the bolts in stage, using a
crisscross pattern.
7. Install:
Kick starter "1"
Plain washer "2"
Bolt (kick starter) "3"
Install the kick starter closest to but
not contacting the pillar tube "4".
8. Install:
Shift pedal "1"
Bolt (shift pedal) "2"
Align the upper line "a" of the shift
pedal with the center "b" of the crank-
case projection and rotate the shift
pedal counterclockwise until it first
engages. Then install the shift pedal.
Bolt (primary drive gear):
48 Nm (4.8 m•kg, 35
ft•lb)
Bolt [crankcase cover
(right)] :
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (kick starter) :
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (shift pedal) :
12 Nm (1.2 m•kg, 8.7
ft•lb)
4-28
YPVS GOVERNOR
YPVS GOVERNOR
REMOVING THE YPVS GOVERNOR
Order Part name Q'ty Remarks
Right crankcase cover
Refer to "KICK SHAFT AND SHIFT SHAFT"
section.
1 Governor assembly 1
2 Dowel pin 1 Refer to removal section.
3 Retainer 1
4Ball 4
5 Retainer weight 1
6 Plain washer 3
7 Thrust bearing 2
8 Collar 1
9Plate 1
10 Compression spring 1
11 Governor gear 1
12 Governor shaft 1
4-29
YPVS GOVERNOR
REMOVING THE GOVERNOR
1. Remove:
Dowel pin "1"
While compressing the spring, re-
move the dowel pin.
CHECKING THE GOVERNOR
GROOVE
1. Inspect:
Washer "1"
•Collar "2"
Wear/Damage Replace.
CHECKING THE BEARING
1. Inspect:
Thrust bearing "1"
Washer "2"
Wear/Damage Replace.
INSTALLING THE GOVERNOR
1. Install:
Governor gear "1"
Compression spring "2"
Plate "3"
Washer "4"
Thrust bearing "5"
•Collar "6"
Retainer weight "7"
To governor shaft "8".
Apply the lithium soap base grease
on the thrust bearing.
2. Install:
Ball "1"
Retainer "2"
To governor shaft "3".
Apply the transmission oil on the re-
tainer and ball.
3. Install:
Dowel pin "1"
While compressing the spring, in-
stall the dowel pin.
Make sure the dowel pin fits into the
groove "a" in the retainer.
4. Install:
Governor assembly "1"
Align the groove "a" in the governor
with the fork "b" and set the governor
in the crankcase cover.
4-30
WATER PUMP
WATER PUMP
DISASSEMBLING THE WATER PUMP
Order Part name Q'ty Remarks
Crankcase cover (right)
Refer to "KICK SHAFT AND SHIFT SHAFT"
section.
1 Water pump housing cover 1
2 Impeller shaft gear 1
3 Dowel pin 1
4 Plain washer 1
5 Impeller shaft assembly 1
6 Bearing 1 Refer to removal section.
7 Oil seal 2 Refer to removal section.
4-31
WATER PUMP
REMOVING THE OIL SEAL
Replace the oil seal when transmis-
sion oil or coolant leaks out from the
water pump housing hole at the bot-
tom.
Do not reuse the removed bearing
and oil seal.
1. Remove:
Bearing "1"
2. Remove:
Oil seal (outside) "1"
Oil seal (inside) "2"
CHECKING THE IMPELLER SHAFT
1. Inspect:
Impeller shaft "1"
Bend/wear/damage Replace.
Fur deposits Clean.
CHECKING THE IMPELLER SHAFT
GEAR
1. Inspect:
Gear teeth "a"
Wear/damage Replace.
CHECKING THE BEARING
1. Inspect:
•Bearing "1"
Rotate inner race with a finger.
Rough spot/seizure Replace.
CHECKING THE OIL SEAL
1. Inspect:
Oil seal "1"
Wear/damage Replace.
INSTALLING THE OIL SEAL
1. Install:
Oil seal (inside) "1"
Oil seal (outside) "2"
Apply the lithium soap base grease
on the oil seal lip.
Install the oil seal with its manufac-
ture's marks or numbers facing the
right crankcase cover "3".
2. Install:
Bearing "1"
Install the bearing by pressing its out-
er race parallel.
INSTALLING THE IMPELLER
SHAFT
1. Install:
Impeller shaft "1"
Take care so that the oil seal lip is
not damaged or the spring does not
slip off its position.
When installing the impeller shaft,
apply the lithium soap base grease
on the oil seal lip and impeller shaft.
And install the shaft while turning it.
2. Install:
Washer "1"
Dowel pin "2"
Impeller shaft gear "3"
•Collar "4"
Washer "5"
Circlip "6"
Install the Impeller shaft gear with the
dowel pin fitted in the groove "a" in
the same gear.
3. Install:
Dowel pin "1"
Gasket (water pump housing cov-
er) "2"
4-32
WATER PUMP
4. Install:
Water pump housing cover "1"
Bolt (water pump housing cover)
"2"
Copper washer (coolant drain
bolt) "3"
Coolant drain bolt "4"
Bolt (water pump hous-
ing cover):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Coolant drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
4-33
CDI MAGNETO
CDI MAGNETO
REMOVING THE CDI MAGNETO
Order Part name Q'ty Remarks
Seat and fuel tank
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
Bolt (Radiator) Refer to "RADIATOR" section.
Disconnect the CDI magneto lead.
1 Left crankcase cover 1
2 Nut (rotor) 1 Refer to removal section.
3 Rotor 1 Refer to removal section.
4 Stator 1
5 Woodruff key 1
4-34
CDI MAGNETO
REMOVING THE ROTOR
1. Remove:
Nut (rotor) "1"
Washer "2"
Use the rotor holding tool "3".
2. Remove:
Rotor "1"
Use the flywheel puller "2".
When installing the flywheel puller,
turn it counterclockwise.
CHECKING THE CDI MAGNETO
1. Inspect:
Rotor inner surface "a"
Stator outer surface "b"
Damage Inspect the crank-
shaft runout and crankshaft bear-
ing.
If necessary, replace CDI magne-
to and/or stator.
CHECKING THE WOODRUFF KEY
1. Inspect:
Woodruff key "1"
Damage Replace.
INSTALLING THE CDI MAGNETO
1. Install:
Stator "1"
Screw (stator) "2"
Temporarily tighten the screws (sta-
tor) at this point.
2. Install:
Woodruff key "1"
Rotor "2"
Clean the tapered portions of the
crankshaft and rotor.
When installing the woodruff key,
make sure that its flat surface "a" is
in parallel with the crankshaft center
line "b".
When installing the rotor, align the
keyway "c" of the rotor with the
woodruff key.
3. Install:
Washer "1"
Nut (rotor) "2"
Use the rotor holding tool "3".
4. Adjust:
Ignition timing
Refer to "CHECKING THE IGNI-
TION TIMING" section in the
CHAPTER 3.
5. Tighten:
Screw (stator) "1"
6. Check:
Ignition timing
Re-check the ignition timing.
7. Connect:
CDI magneto lead "1"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
8. Install:
Gasket (left crankcase cover)
Left crankcase cover "1"
Screw (left crankcase cover) "2"
Tighten the screws in stage, using a
crisscross pattern.
Rotor holding tool:
YU-1235/90890-01235
Flywheel puller:
YM-1189/90890-01189
Nut (rotor):
56 Nm (5.6 m•kg, 40
ft•lb)
Rotor holding tool:
YU-1235/90890-01235
Ignition timing (B.T.D.C):
0.48 mm (0.019 in)
Screw (stator):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Screw [crankcase cover
(left)]:
5 Nm (0.5 m•kg, 3.6
ft•lb)
4-35
ENGINE REMOVAL
ENGINE REMOVAL
REMOVING THE ENGINE
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
Seat and fuel tank
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
Carburetor
Refer to "CARBURETOR AND REED
VALVE" section.
Exhaust pipe and silencer
Refer to "EXHAUST PIPE AND SILENCER"
section.
Clutch cable Disconnect at the engine side.
Radiator Refer to "RADIATOR" section.
Spark plug cap
Disconnect the CDI magneto lead.
1 Drive chain sprocket cover 1
2 Nut (drive sprocket) 1 Refer to removal section.
3 Lock washer 1 Refer to removal section.
4 Drive sprocket 1 Refer to removal section.
5Clip 1
6 Bolt (brake pedal) 1
26 Nm (2.6 m kg, 19 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
85 Nm (8.5 m kg, 61 ft lb)
75 Nm (7.5 m kg, 54 ft lb)
5 Nm (0.5 m kg, 3.6 ft lb)
34 Nm (3.4 m kg, 24 ft lb)
4-36
ENGINE REMOVAL
7 Brake pedal 1
8 Engine bracket 2
9 Engine mounting bolt 3
10 Pivot shaft 1 Refer to removal section.
11 Engine 1 Refer to removal section.
Order Part name Q'ty Remarks
26 Nm (2.6 m kg, 19 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
64 Nm (6.4 m kg, 46 ft lb)
85 Nm (8.5 m kg, 61 ft lb)
75 Nm (7.5 m kg, 54 ft lb)
5 Nm (0.5 m kg, 3.6 ft lb)
34 Nm (3.4 m kg, 24 ft lb)
4-37
ENGINE REMOVAL
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE DRIVE
SPROCKET
1. Remove:
Nut (drive sprocket) "1"
Lock washer "2"
Straighten the lock washer tab.
Loosen the nut while applying the
rear brake.
2. Remove:
Drive sprocket "1"
Drive chain "2"
Remove the drive sprocket together
with the drive chain.
REMOVING THE ENGINE
1. Remove:
Pivot shaft "1"
If the pivot shaft is pulled all the way
out, the swingarm will come loose. If
possible, insert a shaft of similar di-
ameter into the other side of the
swingarm to support it.
2. Remove:
Engine "1"
From right side.
Make sure that the couplers, hoses
and cables are disconnected.
INSTALLING THE ENGINE
1. Install:
Engine "1"
Install the engine from right side.
Pivot shaft "2"
Nut (pivot shaft) "3"
Engine mounting bolt (lower) "4"
Nut [engine mounting bolt (lower)]
"5"
Engine mounting bolt (front) "6"
Nut [engine mounting bolt (front)]
"7"
Engine bracket "8"
Bolt (engine bracket) "9"
Nut (engine bracket) "10"
Engine mounting bolt (upper) "11"
Nut [engine mounting bolt (up-
per)] "12"
Apply the molybdenum disulfide
grease on the pivot shaft.
INSTALLING THE BRAKE PEDAL
1. Install:
Spring "1"
Brake pedal "2"
O-ring "3"
Bolt (brake pedal) "4"
Clip "5"
Apply the lithium soap base grease
on the bolt, O-rings and brake pedal
bracket.
INSTALLING THE DRIVE
SPROCKET
1. Install:
Drive sprocket "1"
Drive chain "2"
Install the drive sprocket together
with the drive chain.
Nut (Pivot shaft):
85 Nm (8.5 m•kg, 61
ft•lb)
Nut [engine mounting
bolt (lower)]:
64Nm (6.4 m•kg, 46
ft•lb)
Nut [engine mounting
bolt (front)]:
64 Nm (6.4 m•kg, 46
ft•lb)
Nut (engine bracket):
34 Nm (3.4 m•kg, 24
ft•lb)
Nut [engine mounting
bolt (upper)]:
34 Nm (3.4 m•kg, 24
ft•lb)
Bolt (brake pedal):
26 Nm (2.6 m•kg, 19
ft•lb)
4-38
ENGINE REMOVAL
2. Install:
Lock washer "1"
Nut (drive sprocket) "2"
Tighten the nut while applying the
rear brake.
3. Bend the lock washer tab to lock
the nut.
4. Install:
Drive chain sprocket guide "1"
Drive chain sprocket cover "2"
Screw (drive chain sprocket cov-
er) "3"
Nut (drive sprocket):
75 Nm (7.5 m•kg, 54
ft•lb)
Screw (drive chain
sprocket cover):
5 Nm (0.5 m•kg, 3.6
ft•lb)
4-39
CRANKCASE AND CRANKSHAFT
CRANKCASE AND CRANKSHAFT
REMOVING THE CRANKSHAFT
Order Part name Q'ty Remarks
Engine Refer to "ENGINE REMOVAL" section.
Piston
Refer to "CYLINDER HEAD, CYLINDER
AND PISTON" section.
Primary drive gear
Refer to "KICK SHAFT AND SHIFT SHAFT"
section.
Kick idle gear
Refer to "KICK SHAFT AND SHIFT SHAFT"
section.
Stopper lever
Refer to "KICK SHAFT AND SHIFT SHAFT"
section.
Rotor and stator Refer to "CDI MAGNETO" section.
1 Segment 1 Refer to removal section.
2 Bolt [L=45 mm (1.77 in)] 6
3 Bolt [L=55 mm (2.17 in)] 4
4 Bolt [L=65 mm (2.56 in)] 1
5 Bolt [L=75 mm (2.95 in)] 1
6 Holder 1
7 Crankcase (right) 1 Refer to removal section.
8 Crankcase (left) 1 Refer to removal section.
30 Nm (3.0 m kg, 22 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
20 Nm (2.0 m kg, 14 ft lb)
14 Nm (1.4 m kg, 10 ft lb)
4-40
CRANKCASE AND CRANKSHAFT
9 Crankshaft 1 Refer to removal section.
10 Oil seal 2
11 Bearing 2 Refer to removal section.
Order Part name Q'ty Remarks
30 Nm (3.0 m kg, 22 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
20 Nm (2.0 m kg, 14 ft lb)
14 Nm (1.4 m kg, 10 ft lb)
4-41
CRANKCASE AND CRANKSHAFT
REMOVING THE SEGMENT
1. Remove:
Bolt (segment) "1"
Segment "2"
Turn the segment counterclockwise
until it stops and loosen the bolt.
If the segment gets an impact, it
may be damaged. Take care not to
give an impact to the segment
when removing the bolt.
DISASSEMBLING THE
CRANKCASE
1. Remove:
Crankcase (right) "1"
Use the flywheel puller "2".
Make appropriate bolts "3" as
shown available by yourself and at-
tach the tool with them.
Fully tighten the tool holding bolts,
but make sure the tool body is par-
allel with the case. If necessary,
one screw may be backed out
slightly to level tool body.
As pressure is applied, alternately
tap on the engine mounting boss
and transmission shafts.
Use soft hammer to tap on the
case half. Tap only on reinforced
portions of case. Do not tap on
gasket mating surface. Work slow-
ly and carefully. Make sure the
case halves separate evenly. If one
end "hangs up", take pressure off
the push screw, realign, and start
over. If the cases do not separate,
check for a remaining case bolt or
fitting. Do not force.
REMOVING THE CRANKSHAFT
1. Remove:
Crankshaft "1"
Use the crankcase separating
tool "2".
Make appropriate bolts "3" as shown
available by yourself and attach the
tool with them.
Do not use a hammer to drive out
the crankshaft.
REMOVING THE CRANKCASE
BEARING
1. Remove:
•Bearing "1"
Remove the bearing from the
crankcase by pressing its inner race
as shown in "A".
If the bearing is removed together
with the crankshaft, remove the
bearing using a general bearing
puller "2" as shown in "B".
Do not use the removed bearing.
CHECKING THE CRANKCASE
1. Inspect:
Contacting surface "a"
Scratches Replace.
Engine mounting boss "b", crank-
case
Cracks/damage Replace.
2. Inspect:
Bearing "1"
Rotate inner race with a finger.
Rough spot/seizure Replace.
3. Inspect:
Oil seal "1"
Damage Replace.
CHECKING THE CRANKSHAFT
1. Measure:
Runout limit "a"
Small end free play limit "b"
Connecting rod big end side
clearance "c"
Crank width "d"
Out of specification Replace.
Use the dial gauge and a thick-
ness gauge.
Flywheel puller:
YU-33270-B/90890-
01362
Crankcase separating
tool:
YU-1135-A/90890-
01135
Dial gauge and stand:
YU-3097/90890-01252
4-42
CRANKCASE AND CRANKSHAFT
INSTALLING THE CRANKCASE
BEARING
1. Install:
Bearing "1"
To left and right crankcase.
Install the bearing by pressing its out-
er race parallel.
INSTALLING THE OIL SEAL
1. Install:
Oil seal (left) "1"
Oil seal (right) "2"
Apply the lithium soap base grease
on the oil seal lip.
Install the oil seal with its manufac-
ture's marks or numbers facing out-
ward.
INSTALLING THE CRANKSHAFT
1. Install:
Crankshaft "1"
Use the crankshaft installing tools
"2", "3", "4".
Hold the connecting rod at top dead
center with one hand while turning
the nut of the installing tool with the
other. Operate the installing tool un-
til the crankshaft bottoms against
the bearing.
Before installing the crankshaft,
clean the contacting surface of
crankcase.
Apply molybdenum disulfide grease
to the surface "a" where the crank-
shaft and bearing come in contact.
Apply the lithium soap base grease
on the oil seal lip.
Do not use a hammer to drive in
the crankshaft.
A. For USA and CDN
B. Except for USA and CDN
2. Check:
Shifter operation
Transmission operation
Unsmooth operation Repair.
3. Apply:
Sealant
On the right crankcase "1".
Clean the contacting surface of left
and right crankcase before applying
the sealant.
4. Install:
Dowel pin "1"
O-ring "2"
5. Install:
Right crankcase "1"
Use the crankshaft installing tool
"2", "3", "4".
Standard <Limit>
Runout
limit:
0.03 mm
(0.0012 in)
0.05 mm
(0.002 in)
Small
end free
play:
0.8–1.0 mm
(0.031–
0.039 in)
2.0 mm
(0.08 in)
Side
clear-
ance:
0.06–0.64
mm (0.002–
0.025 in)
Crack
width:
55.90–55.95
mm (2.201–
2.203 in)
Crankshaft installing pot
"2":
YU-90050/90890-01274
Crankshaft installing bolt
"3":
YU-90050/90890-01275
Adapter "4":
YU-90063/90890-01278
Yamaha Bond No.1215
(ThreeBond
®
No.1215):
90890-85505
Crankshaft installing pot
"2":
YU-90050/90890-01274
Crankshaft installing bolt
"3":
YU-90050/90890-01275
Adapter "4":
YM-01499/90890-01499
4-43
CRANKCASE AND CRANKSHAFT
Apply molybdenum disulfide grease
to the surface "a" where the crank-
shaft and bearing come in contact.
Use two plain washers (Yamaha
genuine: 90201-243K3) "5" or the
ones of a size as shown one on the
other. (Except for USA and CDN)
Install so that the plain washers do
not deviate from the crankshaft cen-
ter. (Except for USA and CDN)
When installing the crankcase, the
connecting rod should be posi-
tioned at TDC (top dead center).
Install while checking that the dowel
pin is in place.
A. For USA and CDN
B. Except for USA and CDN
6. Install:
Clamp "1"
Bolt (crankcase) "2"
Tighten the crankcase tightening
bolts in stage, using a crisscross pat-
tern.
7. Install:
Holder "1"
Bolt (holder) "2"
8. Install:
Segment "1"
Bolt (segment) "2"
When installing the segment onto
the shift cam "3", align the punch
mark "a" with the dowel pin "b".
Turn the segment clockwise until it
stops and tighten the bolt.
If the segment gets an impact, it
may be damaged. Take care not to
give an impact to the segment
when tightening the bolt.
9. Remove:
Sealant
Forced out on the cylinder mating
surface.
10. Apply:
Engine oil
To the crank pin, bearing, oil de-
livery hole and connecting rod big
end washer.
11. Check:
Crankshaft and transmission op-
eration.
Unsmooth operation Repair.
If the crankshaft will not turn smooth-
ly, make an adjustment by gently tap-
ping its right end with a soft hammer.
Bolt (crankcase):
14 Nm (1.4 m•kg, 10
ft•lb)
Bolt (holder):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (segment):
30 Nm (3.0 m•kg, 22
ft•lb)
4-44
TRANSMISSION, SHIFT CAM AND SHIFT FORK
TRANSMISSION, SHIFT CAM AND SHIFT FORK
REMOVING THE TRANSMISSION, SHIFT CAM AND SHIFT FORK
Order Part name Q'ty Remarks
Engine Refer to "ENGINE REMOVAL" section.
Separate the crankcase.
Refer to "CRANKCASE AND CRANK-
SHAFT" section.
1 Guide bar (long) 1
2 Guide bar (short) 1
3 Shift cam 1
4 Shift fork 3 1
5 Shift fork 1 1
6 Shift fork 2 1
7 Main axle 1 Refer to removal section.
8 Drive axle 1 Refer to removal section.
9 Collar 1
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
4-45
TRANSMISSION, SHIFT CAM AND SHIFT FORK
REMOVING THE TRANSMISSION
1. Remove:
Main axle "1"
Drive axle "2"
Tap lightly on the transmission drive
axle with a soft hammer to remove.
Remove assembly carefully. Note
the position of each part. Pay partic-
ular attention to the location and di-
rection of shift forks.
CHECKING THE GEARS
1. Inspect:
Matching dog "a"
Gear teeth "b"
Shift fork groove "c"
Wear/damage Replace.
2. Check:
Gears movement
Unsmooth movement Repair
or replace.
CHECKING THE BEARING
1. Inspect:
Bearing "1"
Rotate inner race with a finger.
Rough spot/seizure Replace.
CHECKING THE SHIFT FORK,
SHIFT CAM AND SEGMENT
1. Inspect:
Shift fork "1"
Wear/damage/scratches Re-
place.
2. Inspect:
Shift cam "1"
Segment "2"
Guide bar "3"
Wear/damage Replace.
3. Check:
Shift fork movement
On its guide bar.
Unsmooth operation Replace
shift fork and/or guide bar.
For a malfunctioning shift fork, re-
place not only the shift fork itself but
the two gears each adjacent to the
shift fork.
INSTALLING THE TRANSMISSION
1. Install:
6th pinion gear (21T) "1"
3rd/4th pinion gear (17T/17T) "2"
5th pinion gear (20T) "3"
2nd pinion gear (15T) "4"
To main axle "5".
Apply the molybdenum disulfide oil
on the inner and end surface of the
idler gear and on the inner surface of
the sliding gear, then install.
2. Install:
2nd wheel gear (29T) "1"
5th wheel gear (24T) "2"
3rd wheel gear (27T) "3"
4th wheel gear (23T) "4"
6th wheel gear (23T) "5"
1st wheel gear (31T) "6"
To drive axle "7".
Apply the molybdenum disulfide oil
on the inner and end surface of the
idler gear and on the inner surface
of the sliding gear, then install.
Apply the molybdenum disulfide
grease on the inner surface of the
4th wheel gear, then install.
3. Install:
Washer "1"
Circlip "2"
Be sure the circlip sharp-edged cor-
ner "a" is positioned opposite side
to the washer and gear "b".
Be sure the circlip end "c" is posi-
tioned at axle spline groove "d".
4-46
TRANSMISSION, SHIFT CAM AND SHIFT FORK
4. Install:
•Collar "1"
Apply the lithium soap base grease
on the oil seal lip.
When installing the collar into the
crankcase, pay careful attention to
the crankcase oil seal lip.
5. Install:
Main axle "1"
Drive axle "2"
Apply the transmission oil on the
crankcase bearing.
INSTALLING THE SHIFT CAM AND
SHIFT FORK
1. Install:
Shift fork 1 (L) "1"
Shift fork 2 (C) "2"
Shift fork 3 (R) "3"
Mesh the shift fork 1 (L) with the 5th
wheel gear "4" and 3 (R) with the
6th wheel gear "6" on the drive axle.
Mesh the shift fork 2 (C) with the
3rd/4th pinion gear "5" on the main
axle.
2. Install:
Shift cam "1"
Apply the transmission oil on the
shift cam.
Install the shift cam while holding up
the 5th wheel gear "2" and keeping
the shift fork 1 "3" moved in the di-
rection of the arrow.
3. Install:
Guide bar (short) "1"
Guide bar (long) "2"
Apply the transmission oil on the
guide bars.
Be sure the long bar is inserted into
the shift forks 1 and 3 and the short
one into 2.
4. Check:
Shifter operation
Transmission operation
Unsmooth operation Repair.
5-1
FRONT WHEEL AND REAR WHEEL
CHASSIS
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
FRONT WHEEL AND REAR WHEEL
REMOVING THE FRONT WHEEL
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
1 Bolt (axle holder) 4 Only loosening.
2 Nut (front wheel axle) 1
3 Front wheel axle 1
4 Front wheel 1
5 Collar 2
6 Oil seal 2
7 Bearing 2 Refer to removal section.
8 Brake disc 1
5
5-2
FRONT WHEEL AND REAR WHEEL
REMOVING THE REAR WHEEL
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Drive chain puller 2
4 Rear wheel 1 Refer to removal section.
5 Collar 2
6 Rear wheel sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to removal section.
10 Brake disc 1
5-3
FRONT WHEEL AND REAR WHEEL
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE REAR WHEEL
1. Remove:
Wheel "1"
Push the wheel forward and remove
the drive chain "2".
REMOVING THE WHEEL BEARING
1. Remove:
Bearing "1"
Remove the bearing using a general
bearing puller "2".
CHECKING THE WHEEL
1. Measure:
Wheel runout
Out of specification Repair/re-
place.
2. Inspect:
Bearing
Rotate inner race with a finger.
Rough spot/seizure Replace.
Replace the bearings, oil seal and
wheel collar as a set.
CHECKING THE WHEEL AXLE
1. Measure:
Wheel axle bends
Out of specification Replace.
Use the dial gauge "1".
The bending value is shown by one
half of the dial gauge reading.
Do not attempt to straighten a bent
axle.
CHECKING THE BRAKE DISC
1. Measure:
Brake disc deflection (only rear
brake disc)
Use the dial gauge "1".
Out of specification Inspect
wheel runout.
If wheel runout is in good condi-
tion, replace the brake disc.
2. Measure:
Brake disc thickness "a"
Out of specification Replace.
INSTALLING THE FRONT WHEEL
1. Install:
Bearing (left) "1"
Spacer "2"
Bearing (right) "3"
Oil seal "4"
Apply the lithium soap base grease
on the bearing and oil seal lip when
installing.
Use a socket that matches the out-
side diameter of the race of the
bearing.
Left side of bearing shall be in-
stalled first.
Install the oil seal with its manufac-
ture's marks or numbers facing out-
ward.
Do not strike the inner race of the
bearing. Contact should be made
only with the outer race.
Wheel runout limit:
Radial "1": 2.0 mm
(0.08 in)
Lateral "2": 2.0 mm
(0.08 in)
Wheel axle bending limit:
0.5 mm (0.020 in)
Brake disc deflection lim-
it:
Rear:
<Limit>: 0.15 mm
(0.006 in)
Brake disc thickness "a":
Front:
3.0 mm (0.12 in)
<Limit>: 2.5 mm (0.10
in)
Rear:
4.0 mm (0.16 in)
<Limit>: 3.5 mm (0.14
in)
5-4
FRONT WHEEL AND REAR WHEEL
2. Install:
Brake disc "1"
Bolt (brake disc) "2"
Tighten the bolts in stage, using a
crisscross pattern.
3. Install:
•Collar "1"
Apply the lithium soap base grease
on the oil seal lip.
Install the collars with their projec-
tions "a" facing the wheel.
4. Install:
Wheel
Install the brake disc "1" between the
brake pads "2" correctly.
5. Install:
Wheel axle "1"
Apply the lithium soap base grease
on the wheel axle.
6. Install:
Nut (wheel axle) "1"
7. Tighten:
Bolt (axle holder) "1"
Before tightening the bolt, fit the
wheel axle to the axle holder by strok-
ing the front fork several times with
the front brake applied.
INSTALLING THE REAR WHEEL
1. Install:
Bearing (right) "1"
Circlip "2"
Spacer "3"
Bearing (left) "4"
Oil seal "5"
Apply the lithium soap base grease
on the bearing and oil seal lip when
installing.
Install the bearing with seal facing
outward.
Use a socket that matches the out-
side diameter of the race of the
bearing.
Right side of bearing shall be in-
stalled first.
Install the oil seal with its manufac-
ture's marks or numbers facing out-
ward.
Do not strike the inner race of the
bearing. Contact should be made
only with the outer race.
2. Install:
Brake disc "1"
Bolt (brake disc) "2"
Tighten the bolts in stage, using a
crisscross pattern.
3. Install:
Rear wheel sprocket "1"
Bolt (rear wheel sprocket) "2"
Washer (rear wheel sprocket) "3"
Nut (rear wheel sprocket) "4"
Tighten the nuts in stage, using a
crisscross pattern.
Bolt (brake disc):
12 Nm (1.2 m•kg, 8.7
ft•lb)
Nut (wheel axle):
105 Nm (10.5 m•kg, 75
ft•lb)
Bolt (axle holder):
21 Nm (2.1 m•kg, 15
ft•lb)
Bolt (brake disc):
14 Nm (1.4 m•kg, 10
ft•lb)
Nut (rear wheel sprock-
et):
42 Nm (4.2 m•kg, 30
ft•lb)
5-5
FRONT WHEEL AND REAR WHEEL
4. Install:
•Collar "1"
Apply the lithium soap base grease
on the oil seal lip.
5. Install:
Wheel
Install the brake disc "1" between the
brake pads "2" correctly.
6. Install:
Drive chain "1"
Push the wheel "2" forward and install
the drive chain.
7. Install:
Left drive chain puller "1"
Wheel axle "2"
Install the left drive chain puller, and
insert the wheel axle from left side.
Apply the lithium soap base grease
on the wheel axle.
8. Install:
Right drive chain puller "1"
Washer "2"
Nut (wheel axle) "3"
Temporarily tighten the nut (wheel
axle) at this point.
9. Adjust:
Drive chain slack "a"
Refer to "ADJUSTING THE
DRIVE CHAIN SLACK" section in
the CHAPTER 3.
10. Tighten:
Nut (wheel axle) "1"
Locknut "2"
Drive chain slack "a":
48–58 mm (1.9–2.3 in)
Nut (wheel axle):
125 Nm (12.5 m•kg, 90
ft•lb)
Locknut:
19 Nm (1.9 m•kg, 13
ft•lb)
5-6
FRONT BRAKE AND REAR BRAKE
FRONT BRAKE AND REAR BRAKE
REMOVING THE FRONT BRAKE
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
Drain the brake fluid. Refer to removal section.
1 Brake hose holder (protector) 2
2 Union bolt 2
3 Brake hose 1
4 Pad pin plug 1 Remove when loosening the pad pin.
5Pad pin 1
Loosen when disassembling the brake cali-
per.
6 Brake caliper 1
7Brake lever 1
8 Brake master cylinder bracket 1
9 Brake master cylinder 1
5-7
FRONT BRAKE AND REAR BRAKE
REMOVING THE REAR BRAKE
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
Rear wheel
Refer to "FRONT WHEEL AND REAR
WHEEL" section.
Drain the brake fluid. Refer to removal section.
1 Brake pedal 1
2 Brake master cylinder 1
3 Brake hose holder 2
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7Pad pin 1
Loosen when disassembling the brake cali-
per.
8 Brake caliper 1
5-8
FRONT BRAKE AND REAR BRAKE
DISASSEMBLING THE BRAKE CALIPER
Order Part name Q'ty Remarks
A. Front
B. Rear
AB
1Pad pin 11
2 Brake pad 2 2
3 Pad support 1 1
4 Brake caliper piston 2 1 Refer to removal section.
5 Brake caliper piston dust seal 2 1 Refer to removal section.
6 Brake caliper piston seal 2 1 Refer to removal section.
5-9
FRONT BRAKE AND REAR BRAKE
DISASSEMBLING THE BRAKE MASTER CYLINDER
Order Part name Q'ty Remarks
A. Front
B. Rear
1 Brake master cylinder cap 1
2 Diaphragm 1
3 Reservoir float 1
4 Push rod (Front) 1
5 Brake master cylinder boot 1
6 Circlip 1 Use a long nose circlip pliers.
7 Washer 1
8 Push rod (Rear) 1
9 Brake master cylinder kit 1
5-10
FRONT BRAKE AND REAR BRAKE
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
DRAINING THE BRAKE FLUID
1. Remove:
Brake master cylinder cap "1"
Protector (rear brake)
Do not remove the diaphragm.
A. Front
B. Rear
2. Connect the transparent hose "2"
to the bleed screw "1" and place a
suitable container under its end.
A. Front
B. Rear
3. Loosen the bleed screw and drain
the brake fluid while pulling the le-
ver in or pushing down on the
pedal.
Do not reuse the drained brake
fluid.
Brake fluid may erode painted
surfaces or plastic parts. Always
clean up spilled fluid immediate-
ly.
REMOVING THE BRAKE CALIPER
PISTON
1. Remove:
Brake caliper piston
Use compressed air and proceed
carefully.
Cover piston with rag and use ex-
treme caution when expelling
piston from cylinder.
Never attempt to pry out piston.
Caliper piston removal steps:
a. Insert a piece of rag into the brake
caliper to lock one brake caliper.
b. Carefully force the piston out of
the brake caliper cylinder with
compressed air.
A. Front
B. Rear
REMOVING THE BRAKE CALIPER
PISTON SEAL KIT
1. Remove:
Brake caliper piston dust seal "1"
Brake caliper piston seal "2"
Remove the brake caliper piston
seals and brake caliper piston dust
seals by pushing them with a finger.
Never attempt to pry out brake cal-
iper piston seals and brake caliper
piston dust seals.
Replace the brake caliper piston
seals and brake caliper piston dust
seals whenever a caliper is disas-
sembled.
A. Front
B. Rear
CHECKING THE BRAKE MASTER
CYLINDER
1. Inspect:
Brake master cylinder inner sur-
face "a"
Wear/scratches Replace mas-
ter cylinder assembly.
Stains Clean.
Use only new brake fluid.
A. Front
B. Rear
2. Inspect:
Diaphragm "1"
Crack/damage Replace.
A. Front
B. Rear
3. Inspect: (front brake only)
Reservoir float "1"
Damage Replace.
4. Inspect:
Brake master cylinder piston "1"
Brake master cylinder cup "2"
Wear/damage/score marks
Replace brake master cylinder kit.
5-11
FRONT BRAKE AND REAR BRAKE
CHECKING THE BRAKE CALIPER
1. Inspect:
Brake caliper cylinder inner sur-
face "a"
Wear/score marks Replace
brake caliper assembly.
A. Front
B. Rear
2. Inspect:
Brake caliper piston "1"
Wear/score marks Replace
brake caliper piston assembly.
Replace the brake caliper piston
seals and brake caliper piston dust
seals "2" whenever a caliper is dis-
assembled.
CHECKING THE BRAKE HOSE
1. Inspect:
Brake hose "1"
Crack/damage Replace.
HANDLING NOTE
All internal parts should be
cleaned in new brake fluid only.
Internal parts should be lubricat-
ed with brake fluid when in-
stalled.
Replace the brake caliper piston
seals and brake caliper piston
dust seals whenever a caliper is
disassembled.
INSTALLING THE BRAKE
CALIPER PISTON
1. Clean:
Brake caliper
Brake caliper piston seal
Brake caliper piston dust seal
Brake caliper piston
Clean them with brake fluid.
2. Install:
Brake caliper piston seal "1"
Brake caliper piston dust seal "2"
Always use new brake caliper pis-
ton seals and brake caliper piston
dust seals.
Apply the brake fluid on the brake
caliper piston seal.
Apply the silicone grease on the
brake caliper piston dust seal.
Fit the brake caliper piston seals
and brake caliper piston dust seals
onto the slot on brake caliper cor-
rectly.
A. Front
B. Rear
3. Install:
Brake caliper piston "1"
Apply the brake fluid on the piston
wall.
Install the piston with its shallow
depressed side "a" facing the
brake caliper.
Never force to insert.
A. Front
B. Rear
INSTALLING THE FRONT BRAKE
CALIPER
1. Install:
Pad support "1"
Brake pad "2"
Pad pin "3"
Install the brake pads with their pro-
jections "a" into the brake caliper re-
cesses "b".
Temporarily tighten the pad pin at
this point.
2. Install:
Brake caliper "1"
Bolt (brake caliper) "2"
3. Tighten:
Pad pin "3"
4. Install:
Pad pin plug "4"
Bolt (brake caliper):
28 Nm (2.8 m•kg, 20
ft•lb)
Pad pin:
18 Nm (1.8 m•kg, 13
ft•lb)
Pad pin plug:
3 Nm (0.3 m•kg, 2.2
ft•lb)
5-12
FRONT BRAKE AND REAR BRAKE
INSTALLING THE REAR BRAKE
CALIPER
1. Install:
Pad support "1"
Brake pad "2"
Pad pin "3"
Install the brake pads with their pro-
jections "a" into the brake caliper re-
cesses "b".
Temporarily tighten the pad pin at
this point.
2. Install:
Brake disc cover "1"
Bolt (brake disc cover) "2"
3. Install:
Brake caliper "1"
Rear wheel "2"
Refer to "FRONT WHEEL AND
REAR WHEEL" section.
4. Tighten:
Pad pin "3"
5. Install:
Pad pin plug "4"
INSTALLING THE BRAKE
MASTER CYLINDER KIT
1. Clean:
Brake master cylinder
Brake master cylinder kit
Clean them with brake fluid.
2. Install:
Brake master cylinder cup (prima-
ry) "1"
Brake master cylinder cup (sec-
ondary) "2"
To brake master cylinder piston
"3".
Apply the brake fluid on the brake
master cylinder cup.
After installing, cylinder cup
should be installed as shown di-
rection. Wrong installation cause
improper brake performance.
3. Install:
Spring "1"
To brake master cylinder piston
"2".
Install the spring at the smaller diam-
eter side.
4. Install:
Brake master cylinder kit "1"
Washer (front brake) "2"
Push rod (rear brake) "2"
Circlip "3"
Brake master cylinder boot "4"
Push rod (front brake) "5"
To brake master cylinder.
Apply the brake fluid on the brake
master cylinder kit.
Apply the silicone grease on the tip
of the push rod.
When installing the circlip, use a
long nose circlip pliers.
A. Front
B. Rear
INSTALLING THE FRONT BRAKE
MASTER CYLINDER
1. Install:
Brake master cylinder "1"
Brake master cylinder bracket "2"
Bolt (brake master cylinder brack-
et) "3"
Install the bracket so that the arrow
mark "a" face upward.
First tighten the bolts on the upper
side of the brake master cylinder
bracket, and then tighten the bolts
on the lower side.
Bolt (brake disc cover):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Pad pin:
18 Nm (1.8 m•kg, 13
ft•lb)
Pad pin plug:
3 Nm (0.3 m•kg, 2.2
ft•lb)
Bolt (brake master cylin-
der bracket):
9 Nm (0.9 m•kg, 6.5
ft•lb)
5-13
FRONT BRAKE AND REAR BRAKE
2. Install:
Brake lever "1"
Bolt (brake lever) "2"
Nut (brake lever) "3"
Apply the silicone grease on the
brake lever sliding surface, bolt and
tip of the push rod.
INSTALLING THE REAR BRAKE
MASTER CYLINDER
1. Install:
Copper washer "1"
Brake hose "2"
Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake master cylinder.
2. Install:
Brake master cylinder "1"
Bolt (brake master cylinder) "2"
3. Install:
Spring "1"
Brake pedal "2"
O-ring "3"
Bolt (brake pedal) "4"
Clip "5"
Apply the lithium soap base grease
on the bolt, O-rings and brake pedal
bracket.
4. Install:
•Pin "1"
Washer "2"
Cotter pin "3"
After installing, check the brake pedal
height. Refer to "ADJUSTING THE
REAR BRAKE" section in the CHAP-
TER 3.
INSTALLING THE FRONT BRAKE
HOSE
1. Install:
Copper washer "1"
Brake hose "2"
Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake caliper.
2. Install:
Brake hose holder "1"
Bolt (brake hose holder) "2"
Align the top "a" of the brake hose
holder with the paint "b" of the brake
hose.
3. Pass the brake hose through the
cable guide "1".
Bolt (brake lever):
6 Nm (0.6 m•kg, 4.3
ft•lb)
Nut (brake lever):
6 Nm (0.6 m•kg, 4.3
ft•lb)
Union bolt:
30 Nm (3.0 m•kg, 22
ft•lb)
Bolt (brake master cylin-
der):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (brake pedal):
26 Nm (2.6 m•kg, 19
ft•lb)
Union bolt:
30 Nm (3.0 m•kg, 22
ft•lb)
Bolt (brake hose holder):
8 Nm (0.8 m•kg, 5.8
ft •lb)
5-14
FRONT BRAKE AND REAR BRAKE
4. Install:
Copper washer "1"
Brake hose "2"
Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake master cylinder.
INSTALLING THE REAR BRAKE
HOSE
1. Install:
Copper washer "1"
Brake hose "2"
Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake caliper.
2. Install:
Brake hose holder "1"
Screw (brake hose holder) "2"
After installing the brake hose
holders, make sure the brake hose
does not contact the spring (rear
shock absorber). If it does, correct
its twist.
FILLING THE BRAKE FLUID
1. Fill:
•Brake fluid
Until the fluid level reaches
"LOWER" level line "a".
Use only the designated quality
brake fluid:
otherwise, the rubber seals may
deteriorate, causing leakage and
poor brake performance.
Refill with the same type of brake
fluid;
mixing fluids may result in a
harmful chemical reaction and
lead to poor performance.
Be careful that water does not
enter the master cylinder when
refilling. Water will significantly
lower the boiling point of the flu-
id and may result in vapor lock.
Brake fluid may erode painted sur-
faces or plastic parts. Always
clean up spilled fluid immediately.
A. Front
B. Rear
2. Air bleed:
Brake system
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion in the CHAPTER 3.
3. Inspect:
Brake fluid level
Fluid at lower level Fill up.
Refer to "CHECKING THE
BRAKE FLUID LEVEL" section in
the CHAPTER 3.
Union bolt:
30 Nm (3.0 m•kg, 22
ft•lb)
Union bolt:
30 Nm (3.0 m•kg, 22
ft•lb)
Screw (brake hose hold-
er):
3 Nm (0.3 m•kg, 2.2
ft•lb)
Recommended brake flu-
id:
DOT #4
5-15
FRONT BRAKE AND REAR BRAKE
4. Install:
Reservoir float (front brake)
Diaphragm
Brake master cylinder cap "1"
Screw (brake master cylinder
cap) "2"
After installation, while pulling the
brake lever in or pushing down on
the brake pedal, check whether
there is any brake fluid leaking
where the union bolts are installed
respectively at the brake master
cylinder and brake caliper.
A. Front
B. Rear
5. Install: (rear brake only)
Protector "1"
Bolt (protector) "2"
Screw (bolt) {brake mas-
ter cylinder cap}:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (protector):
7 Nm (0.7 m•kg, 5.1
ft•lb)
5-16
FRONT FORK
FRONT FORK
REMOVING THE FRONT FORK
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
Front wheel
Refer to "FRONT WHEEL AND REAR
WHEEL" section.
Front brake caliper
Refer to "FRONT BRAKE AND REAR
BRAKE" section.
Number plate
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section in the CHAPTER 4.
1 Protector 1
2 Pinch bolt (upper bracket) 2 Only loosening.
3 Damper assembly 1
Loosen when disassembling the front fork.
Refer to removal section.
4 Pinch bolt (lower bracket) 2 Only loosening.
5 Front fork 1
5-17
FRONT FORK
DISASSEMBLING THE FRONT FORK
Order Part name Q'ty Remarks
1 Adjuster 1 Drain the fork oil. Refer to removal section.
2 Fork spring 1
3 Dust seal 1 Refer to removal section.
4 Stopper ring 1 Refer to removal section.
5 Inner tube 1 Refer to removal section.
6 Outer tube 1
7 Piston metal 1
8 Slide metal 1
9 Oil seal washer 1
10 Oil seal 1
11 Base valve 1 Drain the fork oil. Refer to removal section.
12 Damper assembly 1 Drain the fork oil. Refer to removal section.
5-18
FRONT FORK
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
The front fork requires careful atten-
tion. So it is recommended that the
front fork be maintained at the deal-
ers.
To prevent an accidental explosion
of air, the following instructions
should be observed:
The front fork with a built-in pis-
ton rod has a very sophisticated
internal construction and is par-
ticularly sensitive to foreign ma-
terial. Use enough care not to
allow any foreign material to
come in when the oil is replaced
or when the front fork is disas-
sembled and reassembled.
Before removing the base valves
or front forks, be sure to extract
the air from the air chamber com-
pletely.
REMOVING THE DAMPER
ASSEMBLY
1. Loosen:
Damper assembly "1"
Before removing the front fork from
the machine, loosen the damper as-
sembly with the cap bolt ring wrench
"2".
REMOVING THE ADJUSTER
1. Drain the outer tube of its front
fork oil at its top.
2. Loosen:
•Adjuster "1"
3. Remove:
•Adjuster "1"
While compressing the inner tube
"2", set the cap bolt ring wrench "4"
between the inner tube and locknut
"3".
Hold the locknut and remove the
adjuster.
Do not remove the locknut as the
damper rod may go into the damp-
er assembly and not be taken out.
REMOVING THE INNER TUBE
1. Remove:
Dust seal "1"
Stopper ring "2"
Using slotted-head screwdriver.
Take care not to scratch the inner
tube.
2. Remove:
Inner tube "1"
Oil seal removal steps:
a. Push in slowly "a" the inner tube
just before it bottoms out and then
pull it back quickly "b".
b. Repeat this step until the inner
tube can be pulled out from the
outer tube.
REMOVING THE BASE VALVE
1. Remove:
Base valve "1"
From damper assembly "2".
Hold the damper assembly with the
cap bolt ring wrench "3" and use the
cap bolt wrench "4" to remove the
base valve.
CHECKING THE DAMPER
ASSEMBLY
1. Inspect:
Damper assembly "1"
Bend/damage Replace.
O-ring "2"
Wear/damage Replace.
The front fork with a built-in piston
rod has a very sophisticated inter-
nal construction and is particularly
sensitive to foreign material.
Use enough care not to allow any
foreign material to come in when
the oil is replaced or when the
front fork is disassembled and re-
assembled.
Cap bolt ring wrench:
YM-01501/90890-01501
Cap bolt ring wrench:
YM-01501/90890-01501
Cap bolt wrench:
YM-01500/90890-01500
Cap bolt ring wrench:
YM-01501/90890-01501
5-19
FRONT FORK
CHECKING THE BASE VALVE
1. Inspect:
Base valve "1"
Wear/damage Replace.
Contamination Clean.
O-ring "2"
Wear/damage Replace.
Piston metal "3"
Wear/damage Replace.
Spring "4"
Damage/fatigue Replace base
valve.
Air bleed screw "5"
Wear/damage Replace.
CHECKING THE COLLAR
1. Inspect:
Piston metal "1"
Wear/damage Replace.
CHECKING THE FORK SPRING
1. Measure:
Fork spring free length "a"
Out of specification Replace.
CHECKING THE INNER TUBE
1. Inspect:
Inner tube surface "a"
Score marks Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece Re-
place.
Inner tube bends
Out of specification Replace.
Use the dial gauge "1".
The bending value is shown by one
half of the dial gauge reading.
Do not attempt to straighten a bent
inner tube as this may dangerous-
ly weaken the tube.
CHECKING THE OUTER TUBE
1. Inspect:
Outer tube "1"
Score marks/wear/damage
Replace.
CHECKING THE ADJUSTER
1. Inspect:
•Adjuster "1"
O-ring "2"
Wear/damage Replace.
ASSEMBLING THE FRONT FORK
1. Wash the all parts in a clean sol-
vent.
2. Stretch the damper assembly ful-
ly.
3. Fill:
Front fork oil "1"
To damper assembly.
Be sure to use recommended
fork oil. If other oils are used,
they may have an excessively ad-
verse effect on the front fork per-
formance.
Never allow foreign materials to
enter the front fork.
4. After filling, pump the damper as-
sembly "1" slowly up and down
(about 200 mm (7.9 in) stroke)
several times to bleed the damper
assembly of air.
Be careful not to excessive full stroke.
A stroke of 200 mm (7.9 in) or more
will cause air to enter. In this case, re-
peat the steps 2 to 4.
5. Measure:
Oil level (left and right) "a"
Out of specification Adjust.
Fork spring free length
"a":
454 mm (17.9 in)
<Limit>: 449 mm (17.7
in)
Inner tube bending limit:
0.2 mm (0.008 in)
Recommended oil:
Suspension oil "S1"
Oil capacity:
199 cm
3
(7.00 Imp oz,
6.73 US oz)
Standard oil level "a":
145–148 mm (5.71–5.83
in)
From top of fully
stretched damper as-
sembly.
5-20
FRONT FORK
6. Tighten:
Locknut "1"
Fully finger tighten the locknut onto
the damper assembly.
7. Loosen:
Compression damping adjuster
"1"
Loosen the compression damping
adjuster finger tight.
Record the set position of the ad-
juster (the amount of turning out the
fully turned in position).
8. Install:
Base valve "1"
To damper assembly "2".
First bring the damper rod pressure to
a maximum. Then install the base
valve while releasing the damper rod
pressure.
9. Check:
Damper assembly
Not fully stretched Repeat the
steps 2 to 8.
10. Tighten:
Base valve "1"
Hold the damper assembly with the
cap bolt ring wrench "2" and use the
cap bolt wrench "3" to tighten the
base valve with specified torque.
11. After filling, pump the damper as-
sembly "1" slowly up and down
more than 10 times to distribute
the fork oil.
12. While protecting the damper as-
sembly "1" with a rag and com-
pressing fully, allow excessive oil
to overflow on the base valve
side.
Take care not to damage the damp-
er assembly.
13. Allow the overflowing oil to es-
cape at the hole "a" in the damper
assembly.
The overflow measures about 8 cm
3
(0.28 Imp oz, 0.27 US oz).
14. Check:
Damper assembly smooth move-
ment
Tightness/binding/rough spots
Repeat the steps 2 to 13.
15. Install:
Dust seal "1"
Stopper ring "2"
Oil seal "3"
Oil seal washer "4"
Slide metal "5"
To inner tube "6".
Apply the fork oil on the inner tube.
When installing the oil seal, use vi-
nyl seat "a" with fork oil applied to
protect the oil seal lip.
Install the oil seal with its manufac-
ture's marks or number facing the
axle holder side.
16. Install:
Piston metal "1"
Install the piston metal onto the slot
on inner tube.
Base valve:
29 Nm (2.9 m•kg, 21
ft• lb)
Cap bolt wrench:
YM-01500/90890-01500
Cap bolt ring wrench:
YM-01501/90890-01501
5-21
FRONT FORK
17. Install:
Outer tube "1"
To inner tube "2".
18. Install:
Slide metal "1"
Oil seal washer "2"
To outer tube slot.
Press the slide metal into the outer
tube with fork seal driver "3".
19. Install:
Oil seal "1"
Press the oil seal into the outer tube
with fork seal driver "2".
20. Install:
Stopper ring "1"
Fit the stopper ring correctly in the
groove in the outer tube.
21. Install:
Dust seal "1"
Apply the lithium soap base grease
on the inner tube.
22. Check:
Inner tube smooth movement
Tightness/binding/rough spots
Repeat the steps 15 to 21.
23. Measure:
Distance "a"
Out of specification Turn into
the locknut.
24. Install:
Collar "1"
Fork spring "2"
To damper assembly "3".
Install the collar with its larger diame-
ter end "a" facing the fork spring.
25. Install:
Damper assembly "1"
To inner tube "2".
To install the damper assembly
into the inner tube, hold the inner
tube aslant. If the inner tube is held
vertically, the damper assembly
may fall into it, damaging the valve
inside.
26. Loosen:
Rebound damping adjuster "1"
Loosen the rebound damping ad-
juster finger tight.
Record the set position of the ad-
juster (the amount of turning out the
fully turned in position).
27. Install:
Push rod "1"
Copper washer "2"
•Adjuster "3"
To damper assembly "4".
While compressing the inner tube
"5", set the cap bolt ring wrench "7"
between the inner tube and locknut
"6".
Fully finger tighten the adjuster onto
the damper assembly.
Fork seal driver:
YM-A0948/90890-01502
Fork seal driver:
YM-A0948/90890-01502
Distance "a":
16 mm (0.63 in) or more
Between the damper
assembly "1" bottom
and locknut "2" bot-
tom.
Cap bolt ring wrench:
YM-01501/90890-01501
5-22
FRONT FORK
28. Inspect:
Gap "a" between the adjuster "1"
and locknut "2".
Out of specification Retighten
and readjust the locknut.
If the adjuster is installed out of spec-
ification, proper damping force can-
not be obtained.
29. Tighten:
Adjuster (locknut) "1"
Hold the locknut "2" and tighten the
adjuster with specified torque.
30. Install:
Adjuster "1"
To inner tube.
31. Fill:
Front fork oil "1"
From outer tube top.
Never fail to make the oil amount
adjustment between the maximum
and minimum amount and always
adjust each front fork to the same
setting. Uneven adjustment can
cause poor handling and loss of
stability.
Be sure to use recommended
fork oil. If other oils are used,
they may have an excessively ad-
verse effect on the front fork per-
formance.
Never allow foreign materials to
enter the front fork.
32. Install:
Damper assembly "1"
To outer tube.
Temporarily tighten the damper as-
sembly.
33. Install:
Protector guide "1"
INSTALLING THE FRONT FORK
1. Install:
Front fork "1"
Temporarily tighten the pinch bolts
(lower bracket).
Do not tighten the pinch bolts (up-
per bracket) yet.
2. Tighten:
Damper assembly "1"
Use the cap bolt ring wrench "2" to
tighten the damper assembly with
specified torque.
3. Adjust:
Front fork top end "a"
Gap "a" between the ad-
juster and locknut:
0.5–1.0 mm (0.02–0.04
in)
Adjuster (locknut):
29 Nm (2.9 m•kg, 21
ft•lb)
Adjuster:
55 Nm (5.5 m•kg, 40
ft•lb)
Recommended oil:
Suspension oil "S1"
Standard oil amount:
333 cm
3
(11.72 Imp oz,
11.26 US oz)
*335 cm
3
(11.79 Imp oz,
11.33 US oz)
Extent of adjustment:
300–375 cm
3
(10.6–13.2
Imp oz, 10.1–12.7 US
oz)
* For EUROPE
Damper assembly:
30 Nm (3.0 m•kg, 22
ft•lb)
Cap bolt ring wrench:
YM-01501/90890-01501
Front fork top end (stan-
dard) "a":
5 mm (0.20 in)
5-23
FRONT FORK
4. Tighten:
Pinch bolt (upper bracket) "1"
Pinch bolt (lower bracket) "2"
Tighten the lower bracket to speci-
fied torque. If torqued too much, it
may cause the front fork to mal-
function.
5. Install:
Protector "1"
Bolt (protector) "2"
6. Adjust:
Rebound damping force
Turn in the damping adjuster "1" fin-
ger-tight and then turn out to the orig-
inally set position.
7. Adjust:
Compression damping force
Turn in the damping adjuster "1" fin-
ger-tight and then turn out to the orig-
inally set position.
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Pinch bolt (lower brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Bolt (protector):
5 Nm (0.5 m•kg, 3.6
ft•lb)
5-24
HANDLEBAR
HANDLEBAR
REMOVING THE HANDLEBAR
Order Part name Q'ty Remarks
Number plate Remove the band only.
1 Clutch cable 1 Disconnect at the lever side.
2 Clutch lever holder 1
3 Engine stop switch 1
4 Brake master cylinder 1 Refer to removal section.
5 Throttle cable cap 1 Turn over the cap cover.
6 Throttle cable 1 Disconnect at the throttle side.
7 Throttle 1 Loosen the bolts.
8 Cap cover 1
9 Collar 1
10 Left grip 1 Refer to removal section.
11 Handlebar upper holder 2
12 Handlebar 1
13 Handlebar lower holder 2
4 Nm (0.4 m kg, 2.9 ft lb)
4 Nm (0.4 m kg, 2.9 ft lb)
4 Nm (0.4 m kg, 2.9 ft lb)
9 Nm (0.9 m kg, 6.5 ft lb)
28 Nm (2.8 m kg, 20 ft lb)
40 Nm (4.0 m kg, 29 ft lb)
0.5 Nm (0.05 m kg, 0.36 ft lb)
0.5 Nm (0.05 m kg, 0.36 ft lb)
5-25
HANDLEBAR
DISASSEMBLING THE THROTTLE
Order Part name Q'ty Remarks
1 Grip cap (lower) 1
2 Grip cap (upper) 1
3 Grip assembly 1
4 Grip (right) 1 Refer to removal section.
5 Tube guide 1
5-26
HANDLEBAR
REMOVING THE BRAKE MASTER
CYLINDER
1. Remove:
Brake master cylinder bracket "1"
Brake master cylinder "2"
Do not let the brake master cylin-
der hang on the brake hose.
Keep the brake master cylinder
cap side horizontal to prevent air
from coming in.
REMOVING THE GRIP
1. Remove:
•Grip "1"
Blow in air between the handlebar or
tube guide and the grip. Then remove
the grip which has become loose.
CHECKING THE HANDLEBAR
1. Inspect:
Handlebar "1"
Bends/cracks/damage Re-
place.
Do not attempt to straighten a bent
handlebar as this may dangerous-
ly weaken the handlebar.
ASSEMBLING THE THROTTLE
1. Remove:
Grip (right) "1"
Apply the adhesive on the tube
guide "2".
Before applying the adhesive, wipe
off grease or oil on the tube guide
surface "a" with a lacquer thinner.
Align the mating mark "b" on the
grip (right) with the slot "c" in the
tube guide.
2. Install:
Grip cap (upper) "1"
Grip cap (lower) "2"
Bolt (grip cap) "3"
Temporarily tighten the bolts (grip
cap).
INSTALLING THE HANDLEBAR
1. Install:
Handlebar lower holder "1"
Washer "2"
Nut (handlebar lower holder) "3"
Install the handlebar lower holder
with its side having the greater dis-
tance "a" from the mounting bolt
center facing forward.
Apply the lithium soap base grease
on the thread of the handlebar low-
er holders.
Installing the handlebar lower hold-
er in the reverse direction allows the
front-to-rear offset amount of the
handlebar position to be changed.
Do not tighten the nuts yet.
2. Install:
Handlebar "1"
Handlebar upper holder "2"
Bolt (handlebar upper holder) "3"
The handlebar upper holder should
be installed with the punched mark
"a" forward.
Install the handlebar so that the
marks "b" are in place on both
sides.
Install the handlebar so that the pro-
jection "c" of the handlebar upper
holder is positioned at the mark on
the handlebar as shown.
First tighten the bolts on the front
side of the handlebar upper holder,
and then tighten the bolts on the
rear side.
Bolt (handlebar upper
holder):
28 Nm (2.8 m•kg, 20
ft•lb)
5-27
HANDLEBAR
3. Tighten:
Nut (handlebar lower holder) "1"
4. Install:
Left grip "1"
Apply the adhesive to the handle-
bar "2".
Before applying the adhesive, wipe
off grease or oil on the handlebar
surface "a" with a lacquer thinner.
Install the left grip to the handlebar
so that the line "b" between the two
arrow marks faces straight upward.
5. Install:
•Collar "1"
Grip cap cover "2"
Throttle grip "3"
Apply the lithium soap base grease
on the throttle grip sliding surface.
Tighten the grip cap bolts temporar-
ily without the throttle being fixed to
the handlebar.
6. Install:
Throttle cables "1"
To tube guide "2".
Apply the lithium soap base grease
on the throttle cable end and tube
guide cable winding portion.
7. Install:
Roller "1"
Collar "2"
Apply the lithium soap base grease
on the roller sliding surface and ca-
ble guide.
Install the roller so that the "UP-
PER" mark "a" faces upward.
Pass the throttle cable in the groove
"b" in the roller.
8. Install:
Throttle cable cap "1"
Screw (throttle cable cap) "2"
9. Adjust:
Throttle grip free play
Refer to "ADJUSTING THE
THROTTLE GRIP FREE PLAY"
section in the CHAPTER 3.
10. Install:
Cap cover "1"
11. Install:
Brake master cylinder "1"
Brake master cylinder bracket "2"
Bolt (brake master cylinder brack-
et) "3"
Install the bracket so that the arrow
mark "a" faces upward.
First tighten the bolt on the upper
side of the brake master cylinder
bracket, and then tighten the bolt on
the lower side.
12. Install:
Bolt (grip cap) "1"
Nut (handlebar lower
holder):
40 Nm (4.0 m•kg, 29
ft•lb)
Screw (throttle cable
cap):
0.5 Nm (0.05 m•kg, 0.36
ft•lb)
Bolt (brake master cylin-
der bracket):
9 Nm (0.9 m•kg, 6.5
ft•lb)
Bolt (grip cap):
4 Nm (0.4 m•kg, 2.9
ft•lb)
5-28
HANDLEBAR
After tightening the bolts, check
that the throttle grip "2" moves
smoothly. If it does not, retighten
the bolts for adjustment.
13. Install:
Engine stop switch "1"
•Clutch lever holder "2"
Bolt (clutch lever holder) "3"
Clamp "4"
The engine stop switch, clutch lever
holder and clamp should be in-
stalled according to the dimensions
shown.
Pass the engine stop switch lead in
the middle of the clutch lever hold-
er.
14. Install:
Clutch cable "1"
Apply the lithium soap base grease
on the clutch cable end.
15. Adjust:
Clutch lever free play
Refer to "ADJUSTING THE
CLUTCH LEVER FREE PLAY"
section in the CHAPTER 3.
Bolt (clutch lever holder):
4 Nm (0.4 m•kg, 2.9
ft•lb)
(0.55 in)
14 mm
12 mm
5-29
STEERING
STEERING
REMOVING THE STEERING
Order Part name Q'ty Remarks
TIGHTENING STEPS:
Tighten ring nut. 38 Nm (3.8 m•kg, 27 ft•lb)
Loosen it one turn.
Retighten it. 7 Nm (0.7 m•kg, 5.1 ft•lb)
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
Number plate
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section in the CHAPTER 4.
Handlebar Refer to "HANDLEBAR" section.
Front fender
1 Steering stem nut 1
2 Front fork 2 Refer to "FRONT FORK" section.
3 Upper bracket 1
4 Steering ring nut 1 Refer to removal section.
5 Lower bracket 1
6 Bearing race cover 1
7 Upper bearing 1
8 Lower bearing 1 Refer to removal section.
5-30
STEERING
9 Bearing race 2 Refer to removal section.
Order Part name Q'ty Remarks
5-31
STEERING
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE STEERING RING
NUT
1. Remove:
Steering ring nut "1"
Use the steering nut wrench "2".
Support the steering stem so that
it may not fall down.
REMOVING THE LOWER
BEARING
1. Remove:
Lower bearing "1"
Use the floor chisel "2".
Take care not to damage the steer-
ing shaft thread.
REMOVING THE BEARING RACE
1. Remove:
Bearing race "1"
Remove the bearing race using
long rod "2" and the hammer.
CHECKING THE STEERING STEM
1. Inspect:
Steering stem "1"
Bend/damage Replace.
CHECKING THE BEARING AND
BEARING RACE
1. Wash the bearings and bearing
races with a solvent.
2. Inspect:
•Bearing "1"
Bearing race
Pitting/damage Replace bear-
ings and bearing races as a set.
Install the bearing in the bearing
races. Spin the bearings by hand.
If the bearings hang up or are not
smooth in their operation in the
bearing races, replace bearings
and bearing races as a set.
INSTALLING THE LOWER
BRACKET
1. Install:
Lower bearing "1"
Apply the lithium soap base grease
on the dust seal lip and bearing inner
circumference.
2. Install:
Bearing race
Upper bearing "1"
Bearing race cover "2"
Apply the lithium soap base grease
on the bearing and bearing race cov-
er lip.
3. Install:
Lower bracket "1"
Apply the lithium soap base grease
on the bearing, the portion "a" and
thread of the steering stem.
4. Install:
Steering ring nut "1"
Tighten the steering ring nut using
the steering nut wrench "2".
Refer to "CHECKING AND AD-
JUSTING THE STEERING
HEAD" section in the CHAPTER
3.
5. Check the steering stem by turn-
ing it lock to lock. If there is any
binding, remove the steering stem
assembly and inspect the steer-
ing bearings.
Steering nut wrench:
YU-33975/90890-01403
Steering ring nut:
7 Nm (0.7 m•kg, 5.1
ft• lb)
5-32
STEERING
6. Install:
Washer "1"
7. Install:
Front fork "1"
Upper bracket "2"
Temporarily tighten the pinch bolts
(lower bracket).
Do not tighten the pinch bolts (up-
per bracket) yet.
8. Install:
Washer "1"
Steering stem nut "2"
9. After tightening the nut, check the
steering for smooth movement. If
not, adjust the steering by loosen-
ing the steering ring nut little by lit-
tle.
10. Adjust:
Front fork top end "a"
11. Tighten:
Pinch bolt (upper bracket) "1"
Pinch bolt (lower bracket) "2"
Tighten the lower bracket to speci-
fied torque. If torqued too much, it
may cause the front fork to mal-
function.
Steering stem nut:
145 Nm (14.5 m•kg, 105
ft•lb)
Front fork top end (stan-
dard) "a":
5 mm (0.20 in)
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Pinch bolt (lower brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
5-33
SWINGARM
SWINGARM
REMOVING THE SWINGARM
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
Brake hose holder
Refer to "FRONT BRAKE AND REAR
BRAKE" section.
Rear brake caliper
Refer to "FRONT BRAKE AND REAR
BRAKE" section.
Bolt (brake pedal) Shift the brake pedal backward.
Drive chain
1 Drive chain support 1
2 Lower chain tensioner 1
3 Bolt (rear shock absorber-relay arm) 1 Hold the swingarm.
4 Bolt (connecting rod) 1
5 Pivot shaft 1
6 Swingarm 1
5-34
SWINGARM
DISASSEMBLING THE SWINGARM
Order Part name Q'ty Remarks
1 Cap 2 Refer to removal section.
2 Relay arm 1
3 Connecting rod 1
4 Collar 2
5 Oil seal 2
6 Thrust bearing 2
7 Bushing 2
8 Oil seal 8
9 Bearing 10 Refer to removal section.
70 Nm (7.0 m kg, 50 ft lb)
80 Nm (8.0 m kg, 58 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
6 Nm (0.6 m kg, 4.3 ft lb)
5-35
SWINGARM
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE CAP
1. Remove:
Left cap "1"
Remove with a slotted-head screw-
driver inserted under the mark "a" on
the left cap.
REMOVING THE BEARING
1. Remove:
Bearing "1"
Remove the bearing by pressing its
outer race.
CHECKING THE SWINGARM
1. Inspect:
Bearing "1"
Bushing "2"
Free play exists/unsmooth revolu-
tion/rust Replace bearing and
bushing as a set.
2. Inspect:
Oil seal "3"
Damage Replace.
CHECKING THE RELAY ARM
1. Inspect:
Bearing "1"
•Collar "2"
Free play exists/unsmooth revolu-
tion/rust Replace bearing and
collar as a set.
2. Inspect:
Oil seal "3"
Damage Replace.
CHECKING THE CONNECTING
ROD
1. Inspect:
•Bearing "1"
Collar "2"
Free play exists/unsmooth revolu-
tion/rust Replace bearing and
collar as a set.
2. Inspect:
Oil seal "3"
Damage Replace.
INSTALLING THE BEARING AND
OIL SEAL
1. Install:
•Bearing "1"
Oil seal "2"
To swingarm.
Apply the molybdenum disulfide
grease on the bearing when install-
ing.
Install the bearing by pressing it on
the side having the manufacture's
marks or numbers.
First install the outer and then the
inner bearings to a specified depth
from inside.
2. Install:
Bearing "1"
Washer "2"
Oil seal "3"
To relay arm.
Apply the molybdenum disulfide
grease on the bearing when install-
ing.
Install the bearing by pressing it on
the side having the manufacture's
marks or numbers.
Apply the molybdenum disulfide
grease on the washer.
3. Install:
Bearing "1"
Oil seal "2"
To connecting rod.
Apply the molybdenum disulfide
grease on the bearing when install-
ing.
Install the bearing by pressing it on
the side having the manufacture's
marks or numbers.
Installed depth of bear-
ing:
Outer "a": 0 mm (0 in)
Inner "b": 6.5 mm (0.26
in)
Installed depth of bear-
ing "a":
0 mm (0 in)
Installed depth of bear-
ing "a":
0 mm (0 in)
5-36
SWINGARM
INSTALLING THE SWINGARM
1. Install:
Bushing "1"
Thrust bearing "2"
Oil seal "3"
•Collar "4"
To swingarm "5".
Apply the molybdenum disulfide
grease on the bushings, thrust bear-
ings, oil seal lips and contact surfaces
of the collar and thrust bearing.
2. Install:
•Collar "1"
Washer "2"
To relay arm "3".
Apply the molybdenum disulfide
grease on the collars and oil seal lips.
3. Install:
•Collar "1"
To connecting rod "2".
Apply the molybdenum disulfide
grease on the collar and oil seal lips.
4. Install:
Connecting rod "1"
Bolt (connecting rod) "2"
Washer "3"
Nut (connecting rod) "4"
To relay arm "5".
Apply the molybdenum disulfide
grease on the bolt.
5. Install:
Relay arm "1"
Bolt (relay arm) "2"
Washer "3"
Nut (relay arm) "4"
To swingarm.
Apply the molybdenum disulfide
grease on the bolt circumference
and threaded portion.
Do not tighten the nut yet.
6. Install:
Swingarm "1"
Pivot shaft "2"
Apply the molybdenum disulfide
grease on the pivot shaft.
Insert the pivot shaft from right side.
7. Check:
Swingarm side play "a"
Free play exists Replace thrust
bearing.
Swingarm up and down move-
ment "b"
Unsmooth movement/binding/
rough spots Grease or replace
bearings, bushings and collars.
8. Install:
Bolt (connecting rod) "1"
Washer "2"
Nut (connecting rod) "3"
Apply the molybdenum disulfide
grease on the bolt.
Do not tighten the nut yet.
9. Install:
Bolt (rear shock absorber-relay
arm) "1"
Nut (rear shock absorber-relay
arm) "2"
Apply the molybdenum disulfide
grease on the bolt.
Nut (connecting rod):
80 Nm (8.0 m•kg, 58
ft•lb)
Pivot shaft:
85 Nm (8.5 m•kg, 61
ft•lb)
Nut (rear shock absorb-
er-relay arm):
53 Nm (5.3 m•kg, 38
ft•lb)
5-37
SWINGARM
10. Tighten:
Nut (connecting rod) "1"
11. Tighten:
Nut (relay arm) "1"
12. Install:
•Cap "1"
Install the right cap with its mark "a"
facing forward.
13. Install:
Bolt (lower chain tensioner) "1"
Washer "2"
•Collar "3"
Lower chain tensioner "4"
Nut (lower chain tensioner) "5"
14. Install:
Drive chain support "1"
Drive chain support cover "2"
Bolt {drive chain support [L = 50
mm (1.97 in)]} "3"
Nut (drive chain support) "4"
Bolt {drive chain support cover [L
= 10 mm (0.39 in)]} "5"
Nut (connecting rod):
80 Nm (8.0 m•kg, 58
ft•lb)
Nut (relay arm):
70 Nm (7.0 m•kg, 50
ft•lb)
Nut (lower chain tension-
er):
16 Nm (1.6 m•kg, 11
ft•lb)
Nut (drive chain sup-
port):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Bolt (drive chain support
cover):
7 Nm (0.7 m•kg, 5.1
ft•lb)
5-38
REAR SHOCK ABSORBER
REAR SHOCK ABSORBER
REMOVING THE REAR SHOCK ABSORBER
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.
Refer to "HANDLING NOTE".
Seat
Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section in the CHAPTER 4.
Silencer
Refer to "EXHAUST PIPE AND SILENCER"
section in the CHAPTER 4.
1 Clamp (air filter joint) 1 Only loosening.
2Rear frame 1
3 Bolt (rear shock absorber-relay arm) 1 Hold the swingarm.
4 Bolt (rear shock absorber-frame) 1
5 Rear shock absorber 1
6 Locknut 1 Only loosening.
7 Adjuster 1 Only loosening.
8 Spring seat 2
9 Lower spring guide 1
10 Upper spring guide 1
11 Spring (rear shock absorber) 1
53 Nm (5.3 m kg, 38 ft lb)
56 Nm (5.6 m kg, 40 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
32 Nm (3.2 m kg, 23 ft lb)
29 Nm (2.9 m kg, 21 ft lb)
5-39
REAR SHOCK ABSORBER
12 Bearing 2 Refer to removal section.
Order Part name Q'ty Remarks
53 Nm (5.3 m kg, 38 ft lb)
56 Nm (5.6 m kg, 40 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
32 Nm (3.2 m kg, 23 ft lb)
29 Nm (2.9 m kg, 21 ft lb)
5-40
REAR SHOCK ABSORBER
HANDLING NOTE
Support the machine securely so
there is no danger of it falling
over.
This rear shock absorber is pro-
vided with a separate type tank
filled with high-pressure nitro-
gen gas. To prevent the danger
of explosion, read and under-
stand the following information
before handling the shock ab-
sorber. The manufacturer can
not be held responsible for prop-
erty damage or personal injury
that may result from improper
handling.
Never tamper or attempt to dis-
assemble the cylinder or the
tank.
Never throw the rear shock ab-
sorber into an open flame or
other high heat. The rear shock
absorber may explode as a re-
sult of nitrogen gas expansion.
Be careful not to damage any
part of the gas tank. A damaged
gas tank will impair the damp-
ing performance or cause a
malfunction.
Take care not to scratch the
contact surface of the piston
rod with the cylinder; or oil
could leak out.
Never attempt to remove the
plug at the bottom of the nitro-
gen gas tank. It is very danger-
ous to remove the plug.
When scrapping the rear shock
absorber, follow the instruc-
tions on disposal.
NOTES ON DISPOSAL (YAMAHA
DEALERS ONLY)
Before disposing the rear shock ab-
sorber, be sure to extract the nitrogen
gas from valve "1". Wear eye protec-
tion to prevent eye damage from es-
caping gas and/or metal chips.
To dispose of a damaged or worn-
out rear shock absorber, take the
unit to your Yamaha dealer for this
disposal procedure.
REMOVING THE BEARING
1. Remove:
Stopper ring (upper bearing) "1"
Press in the bearing while pressing its
outer race and remove the stopper
ring.
2. Remove:
Upper bearing "1"
Remove the bearing by pressing its
outer race.
3. Remove:
Lower bearing "1"
Remove the bearing by pressing its
outer race.
CHECKING THE REAR SHOCK
ABSORBER
1. Inspect:
Damper rod "1"
Bends/damage Replace rear
shock absorber assembly.
Shock absorber "2"
Oil leaks Replace rear shock
absorber assembly.
Gas leaks Replace rear shock
absorber assembly.
Spring "3"
Damage Replace spring.
Fatigue Replace spring.
Move spring up and down.
Spring guide "4"
Wear/damage Replace spring
guide.
Spring seat "5"
Cracks/damage Replace.
Bearing "6"
Free play exists/unsmooth revolu-
tion/rust Replace.
INSTALLING THE BEARING
1. Install:
Upper bearing "1"
Install the bearing parallel until the
stopper ring groove appears by
pressing its outer race.
Do not apply the grease on the
bearing outer race because it will
wear the rear shock absorber sur-
face on which the bearing is press
fitted.
5-41
REAR SHOCK ABSORBER
2. Install:
Stopper ring (upper bearing) "1"
After installing the stopper ring, push
back the bearing until it contacts the
stopper ring.
3. Install:
Lower bearing "1"
Install the bearing by pressing it on
the side having the manufacture's
marks or numbers.
INSTALLING THE SPRING (REAR
SHOCK ABSORBER)
1. Install:
Spring "1"
Upper spring guide "2"
Lower spring guide "3"
2. Install:
Spring seat "1"
Install the spring seat with the projec-
tion "a" brought into contact with the
spring end, as shown.
3. Tighten:
•Adjuster "1"
4. Adjust:
Spring length (installed)
Refer to "ADJUSTING THE
REAR SHOCK ABSORBER
SPRING PRELOAD" section in
the CHAPTER 3.
5. Tighten:
Locknut "1"
INSTALLING THE REAR SHOCK
ABSORBER
1. Install:
Dust seal "1"
O-ring "2"
Collar "3"
Apply the molybdenum disulfide
grease on the dust seal lips and col-
lars.
Apply the lithium soap base grease
on the O-rings.
2. Install:
Bushing "1"
Collar "2"
Dust seal "3"
Apply the molybdenum disulfide
grease on the bearing and dust seal
lips.
Install the dust seals with their lips
facing inward.
3. Install:
Rear shock absorber
4. Install:
Bolt (rear shock absorber-frame)
"1"
Washer "2"
Nut (rear shock absorber-frame)
"3"
Apply the molybdenum disulfide
grease on the bolt.
5. Install:
Bolt (rear shock absorber-relay
arm) "1"
Nut (rear shock absorber-relay
arm) "2"
Apply the molybdenum disulfide
grease on the bolt.
Installed depth of the
bearing "a":
4 mm (0.16 in)
Nut (rear shock absorb-
er-frame):
56 Nm (5.6 m•kg, 40
ft•lb)
Nut (rear shock absorb-
er-relay arm):
53 Nm (5.3 m•kg, 38
ft•lb)
5-42
REAR SHOCK ABSORBER
6. Install:
Rear frame "1"
Bolt [rear frame (upper)] "2"
Bolt [rear frame (lower)] "3"
7. Tighten:
Bolt (air filter joint) "1"
Bolt [rear frame (upper)]:
32 Nm (3.2 m•kg, 23
ft•lb)
Bolt [rear frame (lower)]:
29 Nm (2.9 m•kg, 21
ft•lb)
Bolt (air filter joint):
2 Nm (0.2 m•kg, 1.4
ft•lb)
6-1
ELECTRICAL
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
6
6-2
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL COMPONENTS
1. Engine stop switch
2. CDI unit
3. Ignition coil
4. CDI magneto
5. Spark plug
WIRING DIAGRAM
1. Engine stop switch
2. CDI unit
3. Ignition coil
4. CDI magneto
5. Spark plug
COLOR CODE
BBlack
O Orange
YYellow
B/R Black/Red
B/W Black/White
G/L Green/Blue
G/W Green/White
W/L White/Blue
W/R White/Red
6-3
IGNITION SYSTEM
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure
and for checking the spark plug which will not spark.
*marked: Only when the ignition checker is used.
Remove the following parts before inspection.
1. Seat
2. Fuel tank
Use the following special tools in this inspection.
Spark gap test Spark *Clean or replace spark plug.
No spark
Check entire ignition system for connection. No good Repair or replace.
OK
Check engine stop switch. No good Replace.
OK
Check ignition coil. (primary coil and secondary
coil)
No good
Replace.
OK
Check spark plug cap. No good Replace.
OK
Check CDI magneto. (pickup coil and charging
coil)
No good
Replace.
OK
Replace CDI unit.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-3112-C/90890-03112
6-4
IGNITION SYSTEM
SPARK GAP TEST
1. Disconnect the spark plug cap
from spark plug.
2. Connect the dynamic spark tester
"1" (ignition checker "2") as
shown.
Ignition coil "3"
Spark plug "4"
A. For USA and CDN
B. Except for USA and CDN
3. Kick the kickstarter crank.
4. Check the ignition spark gap.
5. Start engine, and increase spark
gap until misfire occurs. (for USA
and CDN only)
CHECKING THE COUPLERS,
LEADS AND IGNITION COIL
CONNECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-cir-
cuit Repair or replace.
CHECKING THE ENGINE STOP
SWITCH
1. Inspect:
Engine stop switch conduction
Not conductive while it is pushed
Replace.
Conductive while it is freed Re-
place.
Set the tester selection position to "
Ω × 1".
CHECKING THE IGNITION COIL
1. Inspect:
Primary coil resistance
Out of specification Replace.
2. Inspect:
Secondary coil resistance
Out of specification Replace.
Remove the spark plug cap by turn-
ing it counterclockwise and inspect.
Install the spark plug cap by turning
it clockwise until it is tight.
CHECKING THE SPARK PLUG
CAP
1. Inspect:
Spark plug cap
Loose connection Tighten.
Deteriorated/damaged Re-
place.
Spark plug cap resistance
Out of specification Replace.
Minimum spark gap:
6.0 mm (0.24 in)
Tester (+) leadBlack/White lead
"1"
Tester (-) lead Black lead "2"
Result
Conductive (while the
engine stop switch is
pushed)
Tester (+) lead Yellow lead "1"
Tester (-) lead Black lead "2"
Primary
coil resis-
tance
Tester se-
lector posi-
tion
0.24–0.36
Ω at 20 °C
(68 °F)
Ω × 1
Tester (+) lead Spark plug lead
"1"
Tester (-) lead Yellow lead "2"
Secondary
coil resis-
tance
Tester se-
lector posi-
tion
5.7–8.5
kΩat 20 °C
(68 °F)
kΩ × 1
Tester (+) lead Spark plug lead
terminal "1"
Tester (-) lead Spark plug termi-
nal "2"
Spark plug
cap resis-
tance
Tester se-
lector posi-
tion
4–6 kΩ at
20 °C (68
°F)
kΩ × 1
6-5
IGNITION SYSTEM
CHECKING THE CDI MAGNETO
1. Inspect:
Pickup coil resistance
Out of specification Replace.
2. Inspect:
Charging coil 1 resistance
Out of specification Replace.
3. Inspect:
Charging coil 2 resistance
Out of specification Replace.
CHECKING THE CDI UNIT
Check all electrical components. If no
fault is found, replace the CDI unit.
Then check the electrical compo-
nents again.
Tester (+) lead White/Red lead
"1"
Tester (-) lead White/Blue lead
"2"
Pickup coil
resistance
Tester se-
lector posi-
tion
248–372 Ω
at 20 °C (68
°F)
Ω × 100
Tester (+) lead Black/Red lead
"1"
Tester (-) leadGreen/White lead
"2"
Charging
coil 1 resis-
tance
Tester se-
lector posi-
tion
720–1,080
Ω at 20 °C
(68 °F)
Ω × 100
Tester (+) lead Green/Blue lead
"1"
Tester (-) lead Black lead "2"
Charging
coil 2 resis-
tance
Tester se-
lector posi-
tion
44–66 Ω at
20 °C (68
°F)
Ω × 10
7-1
ENGINE
TUNING
ENGINE
CARBURETOR SETTING
The role of fuel is to cool the engine,
and in the case of a 2-stroke en-
gine, to lubricate the engine in addi-
tion to power generation.
Accordingly, if a mixture of air and
fuel is too lean, abnormal combus-
tion will occur, and engine seizure
may result. If the mixture is too rich,
spark plugs will get wet with oil, thus
making it impossible to bring the en-
gine into full play or if the worst
comes to the worst, the engine may
stall.
The richness of the air-fuel mixture
required for the engine will vary with
atmospheric conditions of the day
and therefore, the settings of the
carburetor must be properly suited
to the atmospheric conditions (air
pressure, humidity and tempera-
ture).
Finally, the rider himself must make
a test-run and check his machine
for conditions (pick-up of engine
speed, road surface conditions)
and for the discoloration of the
spark plug(s). After taking these
into consideration, he must select
the best possible carburetor set-
tings.
It is advisable to make a note of set-
tings, atmospheric conditions, road
surface condition, lap-time, etc. so
that the memorandum can be used
as a reference useful for future.
ATMOSPHERIC CONDITIONS AND
CARBURETOR SETTINGS
The reason for the above tendency is
that the richness or leanness of a fuel
mixture depends on the density of the
air (i.e. the concentration of oxygen in
it).
Higher temperature expands the air
with its resultant reduced density.
Higher humidity reduces the
amount of oxygen in the air by so
much of the water vapor in the
same air.
Lower atmospheric pressure (at a
high altitude) reduces the density of
the air.
TEST RUN
After warming up the engine
equipped with the standard type car-
buretor(s) and spark plug(s), run two
or three laps of the circuit and check
the smooth operation of the engine
and discoloration of spark plug(s).
A. Normal
B. Over burned (too lean)
C. Oil fouled (too rich)
EFFECT OF SETTING PARTS IN
RELATION TO THROTTLE VALVE
OPENING
A. Closed
B. Full-open
1. Pilot air screw
2. Pilot jet
3. Jet needle
4. Diameter of straight portion
5. Clip position
6. Throttle valve
7. Main jet
ADJUSTING THE MAIN JET
The richness of air-fuel mixture with
1/2–4/4 throttle can be set by chang-
ing the main jet "1".
1. Spark plug is too hot.
Select a main jet having higher
calibrating No. than standard. (To
be enriched)
2. Spark plug is wet.
Select a main jet having lower cal-
ibrating No. than standard. (To be
leaned out)
ADJUSTING THE PILOT AIR
SCREW
The richness of the air-fuel mixture
with full closed to 1/4 throttle can be
set by turning the pilot air screw "1".
Turning in the pilot air screw will en-
rich the mixture at low speeds, and
turning out it will lean out the mixture.
Air
temp.
Hu-
midity
Air
pres-
sure
(alti-
tude)
Mix-
ture
Set-
ting
High High
Low
(high)
Rich-
er
Lean-
er
Low Low
High
(low)
Lean-
er
Rich-
er
Discoloration
Condition of spark
plug
Normal
Insulator is dry
and burnt brown.
Over burned
(too lean)
Insulator is whit-
ish.
Oil fouled (too
rich)
Insulator is sooty
and wet.
Standard main jet #430
Standard pilot
air screw posi-
tion
2-1/4 turns out
7-2
ENGINE
ADJUSTING THE PILOT JET
The richness of air-fuel mixture with
the throttle fully closed to 1/2 open
can be set by changing the pilot jet
"1". It is changed when adjustment
cannot be made by the pilot air screw
alone.
ADJUSTING THE JET NEEDLE
GROOVE POSITION
Should the engine be hard to run
smoothly at intermediate speeds, the
jet needle "1" must be adjusted. If the
mixture is too rich or too lean at inter-
mediate speed operation, irregular
engine operation and poor accelera-
tion will result. Whether or not the
richness of the mixture is proper is
hard to be determined by means of
the spark plug and therefore, it should
be judged from your feeling of actual
engine operation.
1. Too rich at intermediate speeds
Rough engine operation is felt
and the engine will not pick up
speed smoothly.
In this case, step up the jet needle
clip by one groove or 0.5 groove
and move down the needle to
lean out the mixture.
2. Too lean at intermediate speeds
The engine breathes hard and will
not pick up speed quickly.
In this case, step down the jet
needle clip by one groove or 0.5
groove and move up the needle to
enrich the mixture.
ADJUSTING THE JET NEEDLE
On the carburetors used in the
YZ125, the main nozzle is a non dis-
assembly type, so it can not be re-
placed. Therefore, carburetor setting
requires the change of the jet needle.
1. The jet needle setting parts, hav-
ing the same taper angle, are
available in different straight por-
tion diameters and in different ta-
per starting positions.
In the case of the same number of clip
position, changing from 6BFY43-74
to 6BFY42-74 has the same effect as
a lowering of 0.5-clip position. And in
the case of the same number of clip
position, changing from 6BFY43-74
to 6BFY44-74 has the same effect as
a rising of 0.5-clip position.
A. Difference in straight portion
diameter.
B. Difference in clip position
a. Reference needle
b. 0.5 richer
c. 0.5 leaner
RELATIONSHIP WITH THROTTLE
OPENING
The flow of the fuel through the car-
buretor main system is controlled by
the main jet and then, it is further reg-
ulated by the area between the main
nozzle and the jet needle. On the re-
lationship between the fuel flow and
the throttle opening, the fuel flow re-
lates to the straight portion of the jet
needle at full closed–1/8 throttle, to
the 1st tapered portion at 1/4 throttle,
to the second tapered portion at 1/2
throttle, to the third tapered portion at
3/4 throttle and to the fourth tapered
portion at full open.
Therefore, the fuel flow is balanced at
each stage of throttle opening by a
combination of the jet needle diame-
ter and clip position.
<Example>
A. Lean (larger diameter)
B. Rich (smaller diameter)
C. 1st taper
D. 2nd taper
E. 3rd taper
F. 4th taper
1. Full closed
2. 1/4 throttle
3. 1/2 throttle
4. 3/4 throttle
5. Full open
a. Main nozzle
Standard pilot jet
#40
*#45
*Except for USA and CDN
Standard clip
position
No.3 groove
Standard jet
needle
6BFY43-74
6BFY43-73
6BFY43-74
6BFY43-75
6BFY44-74
6BFY43-74
6BFY42-74
6BFY43-74-3
6BFY43-74-2
6BFY43-75-3
7
7-3
ENGINE
CARBURETOR SETTING PARTS
Main jet
"1"
Size
Part number
(-14143-)
Rich #470 137-94
#460 137-92
#450 137-90
#440 137-88
(STD) #430 137-86
#420 137-84
#410 137-82
Lean #400 137-80
Pilot jet
"2"
Size
Part number
(-14142-)
Rich #50 4KM-50
#47.5 4KM-47
** (STD) #45 4KM-45
#42.5 4KM-42
* (STD) #40 4KM-40
#37.5 4KM-37
#35 4KM-35
#32.5 4KM-32
Lean #30 4KM-30
Throttle
valve "3"
Size
Part number
(-14112-)
Rich
(STD) 4.0 1C3-40
Lean 4.25 1C3-42
* For USA and CDN
** Except for USA and CDN
Jet nee-
dle "4"
Size
Part
number
(-14116-)
Rich 6BFY44-72 284-K2
6BFY44-73 284-K3
6BFY44-74 284-K4
6BFY44-75 284-K5
Lean 6BFY44-76 284-K6
Rich 6BFY43-72 284-J2
6BFY43-73 284-J3
(STD) 6BFY43-74 284-J4
6BFY43-75 284-J5
Lean 6BFY43-76 284-J6
Rich 6BFY42-72 284-H2
6BFY42-73 284-H3
6BFY42-74 284-H4
6BFY42-75 284-H5
Lean 6BFY42-76 284-H6
* For USA and CDN
** Except for USA and CDN
7-4
ENGINE
ROAD CONDITION AND EXAMPLES OF CARBURETOR SETTING
A. For USA and CDN
B. Except for USA and CDN
SPECIFICATIONS OF JET NEEDLE
EXAMPLES OF CARBURETOR SETTING DEPENDING ON SYMPTOM
General condition Sandy condition
Under 10°C
(50°F)
15–25°C
(59–77°F)
Over 30°C
(86°F)
Under 10°C
(50°F)
15–25°C
(59–77°F)
Over 30°C
(86°F)
(Winter) (Spring, Au-
tumn)
(Summer) (Winter) (Spring, Au-
tumn)
(Summer)
Main jet #440 #430 #420 #460 #450 #440
Jet needle 6BFY44-74-3 6BFY43-74-3 6BFY44-74-2 6BFY43-74-4 6BFY44-74-3 6BFY43-74-3
Pilot jet A #42.5 #40 #40 #42.5 #40 #40
B #47.5 #45 #42.5 #47.5 #45 #42.5
Pilot air screw 2-1/4 2-1/4 2-1/4 2-1/4 2-1/4 2-1/4
Diameter of straight portion
ø2.72 mm
(0.1071 in)
ø2.73 mm
(0.1075 in)
ø2.74 mm
(0.1079 in)
ø2.75 mm
(0.1083 in)
ø2.76 mm
(0.1087 in)
Rich 1 richer 6BFY43-72-4 6BFY43-73-4 6BFY43-74-4 6BFY43-75-4 6BFY43-76-4
0.5 richer
6BFY44-72-3 6BFY44-73-3 6BFY44-74-3 6BFY44-75-3 6BFY44-76-3
6BFY42-72-4 6BFY42-73-4 6BFY42-74-4 6BFY42-75-4 6BFY42-76-4
STD 6BFY43-72-3 6BFY43-73-3 6BFY43-74-3 6BFY43-75-3 6BFY43-76-3
0.5 leaner
6BFY44-72-2 6BFY44-73-2 6BFY44-74-2 6BFY44-75-2 6BFY44-76-2
6BFY42-72-3 6BFY42-73-3 6BFY42-74-3 6BFY42-75-3 6BFY42-76-3
Lean 1 leaner 6BFY43-72-2 6BFY43-73-2 6BFY43-74-2 6BFY43-75-2 6BFY43-76-2
Symptom Setting Checking
At full throttle
Stall at high speeds
*Hard breathing
Shearing noise
Whitish spark plug
Lean mixture
Increase main jet calibration no. (Gradual-
ly)
Discoloration of spark plug If tan color, it
is in good condition.
If cannot be corrected:
Clogged float valve seat
Clogged fuel hose
Clogged fuel cock
At full throttle
Stop of speed pick-up
Slow speed pick-up
Slow response
Sooty spark plug
Rich mixture
Decrease main jet calibration no. (Gradual-
ly)
*In case of racing slight enrichment of mix-
ture reduces engine trouble.
Discoloration of spark plug If tan color, it
is in good condition.
If not effect:
Clogged air filter
Fuel overflow from carburetor
Clogged main air passage or clogged fil-
ter
7-5
ENGINE
This should be taken simply for an example. It is necessary to set the carburetor while checking the operating conditions
of the engine and discoloration of spark plugs. Normally, carburetor setting is made by means of the main jet, jet needle
clip position (including one with 0.5 difference), pilot jet and pilot air screw. If the result of setting is still unsatisfactory, it is
advisable to change the diameter of the straight portion the jet needle.
Lean mixture Lower jet needle clip position. (1 groove
down)
Clip position indicates the position of jet
needle groove, to which the clip is fitted.
The position is numbered from the top.
If a change in the clip position (1 groove) is
effective, try another jet needle that pro-
vides a difference of 0.5 in the clip position.
Rich mixture Raise jet needle clip position. (1 groove up)
1/4–3/4 throttle
*Hard breathing
Lack of speed
Lower jet needle clip position. (1 groove
down)
1/4–1/2 throttle
Slow speed pick-up
White smoke
Poor acceleration
Raise jet needle clip position. (1 groove up)
0–1/4 throttle
*Hard breathing
Speed down
Use jet needle having a smaller diameter. Number of turns-back Correct properly
Overflow from carburetor
0–1/4 throttle
Poor acceleration
White smoke
Use jet needle with a larger diameter.
Unstable at low speeds
Pinking noise
Lower jet needle clip position.
(1 groove down)
Turn in pilot air screw.
Poor response at extremely low
speed
Reduce pilot jet calibration No.
Turn out pilot air screw.
If not effect, reverse the above procedures.
Dragging brake
Overflow from carburetor
Poor response in the range of
low to intermediate speeds
Raise jet needle clip position.
If no effect, reverse the above procedures.
Poor response when throttle is
opened quickly
Check overall settings.
Use main jet having lower calibration no.
Raise jet needle clip position. (1 groove up)
If no effect, reverse the above procedures.
Check air filter for fouling.
Poor engine operation Turn in pilot air screw. Check throttle valve operation.
* In case of hard breathing, check the air vent hose for clogging.
Symptom Setting Checking
Groove 1
Groove 2
Groove 3
Groove 4
Groove 5
Clip
Jet needle
Leaner
(Standard)
Richer
7-6
CHASSIS
CHANGE OF THE HEAT RANGE
OF SPARK PLUGS
Judging from the discoloration of
spark plugs, if they are found improp-
er, it can be corrected by the following
two methods; changing carburetor
settings and changing the heat range
of spark plug.
In principle, it is advisable to first
use spark plugs of standard heat
range, and judging from the discol-
oration of spark plugs, adjust carbu-
retor settings.
If the calibration No. of the main jet
must be changed by ±30, it is advis-
able to change the heat range of
spark plugs and newly select the
proper main jet.
When checking the discoloration of
spark plugs, be sure to stop the en-
gine immediately after a run and
check.
Avoid racing.
When changing the heat range of
spark plugs, never attempt to
change it more than ±1 rank.
When using a spark plug other than
standard, check its heat range
against the standard and check that
it is a resistance type.
Note that even if the discoloration
seems proper, it may slightly vary
with the spark plug maker and oil in
use.
CHASSIS
SELECTION OF THE SECONDARY
REDUCTION RATIO (SPROCKET)
<Requirement for selection of sec-
ondary gear reduction ratio>
It is generally said that the second-
ary gear ratio should be reduced for
a longer straight portion of a speed
course and should be increased for
a course with many corners. Actual-
ly, however, as the speed depends
on the ground condition of the day
of the race, be sure to run through
the circuit to set the machine suit-
able for the entire course.
In actuality, it is very difficult to
achieve settings suitable for the en-
tire course and some settings may
be sacrificed. Thus, the settings
should be matched to the portion of
the course that has the greatest ef-
fect on the race result. In such a
case, run through the entire course
while making notes of lap times to
find the best balance; then, deter-
mine the secondary reduction ratio.
If a course has a long straight por-
tion where a machine can run at
maximum speed, the machine is
generally set such that it can devel-
op its maximum revolutions toward
the end of the straight line, with care
taken to avoid the engine over-rev-
ving.
Riding technique varies from rider to
rider and the performance of a ma-
chine also vary from machine to ma-
chine. Therefore, do not imitate other
rider's settings from the beginning but
choose your own setting according to
the level of your riding technique.
DRIVE AND REAR WHEEL
SPROCKETS SETTING PARTS
TIRE PRESSURE
Tire pressure should be adjust to suit
the road surface condition of the cir-
cuit.
Under a rainy, muddy, sandy, or
slippery condition, the tire pressure
should be lower for a larger area of
contact with the road surface.
Under a stony or hard road condi-
tion, the tire pressure should be
higher to prevent a flat tire.
FRONT FORK SETTING
The front fork setting should be made
depending on the rider's feeling of an
actual run and the circuit conditions.
The front fork setting includes the fol-
lowing three factors:
1. Setting of air spring characteris-
tics
Change the fork oil amount.
2. Setting of spring preload
Change the spring.
3. Setting of damping force
Change the compression damp-
ing.
Change the rebound damping.
The spring acts on the load and
the damping force acts on the
cushion travel speed.
CHANGE IN AMOUNT AND
CHARACTERISTICS OF FORK OIL
Damping characteristic near the final
stroke can be changed by changing
the fork oil amount.
Standard spark
plug
BR9EVX/NGK
(resistance
type)
Secondary reduction ratio =
Number of rear wheel sprocket
teeth/Number of drive sprocket
teeth
Standard second-
ary reduction ratio
3.692 (48/13)
Part name Size Part number
Drive
sprocket
"1"
(STD) 13T 9383B-13218
Rear wheel
sprocket
"2"
47T 1C3-25447-00
(STD) 48T 1C3-25448-00
49T 1C3-25449-00
50T 1C3-25450-00
51T 1C3-25451-00
52T 1C3-25452-00
Standard tire pressure:
100 kPa (1.0 kgf/cm
2
,
15 psi)
Extent of adjustment:
60–80 kPa (0.6–0.8
kgf/cm
2
, 9.0–12 psi)
Extent of adjustment:
100–120 kPa (1.0–1.2
kgf/cm
2
, 15–18 psi)
7-7
CHASSIS
Adjust the oil amount in 5 cm
3
(0.2
Imp oz, 0.2 US oz) increments or
decrements. Too small oil amount
causes the front fork to produce a
noise at full rebound or the rider to
feel some pressure on his hands
or body. Alternatively, too large oil
amount will cause the air spring
characteristics to have a tendency
to be stiffer with the consequent
deteriorated performance and
characteristics. Therefore, adjust
the front fork within the specified
range.
A. Air spring characteristics in
relation to oil amount change
B. Load
C. Stroke
1. Max. oil amount
2. Standard oil amount
3. Min. oil amount
SETTING OF SPRING AFTER
REPLACEMENT
As the front fork setting can be easily
affected by rear suspension, take
care so that the machine front and
rear are balanced (in position, etc.)
when setting the front fork.
1. Use of soft spring
Change the rebound damping.
Turn out one or two clicks.
Change the compression damp-
ing.
Turn in one or two clicks.
Generally a soft spring gives a soft
riding feeling. Rebound damping
tends to become stronger and the
front fork may sink deeply over a se-
ries of gaps.
2. Use of stiff spring
Change the rebound damping.
Turn in one or two clicks.
Change the compression damp-
ing.
Turn out one or two clicks.
Generally a stiff spring gives a stiff
riding feeling. Rebound damping
tends to become weaker, resulting in
lack of a sense of contact with the
road surface or in a vibrating handle-
bar.
FRONT FORK SETTING PARTS
Front fork spring "1"
The I.D. mark (slits) "a" is proved on
the end of the spring.
REAR SUSPENSION SETTING
The rear suspension setting should
be made depending on the rider's
feeling of an actual run and the circuit
conditions.
The rear suspension setting includes
the following two factors:
1. Setting of spring preload
Change the set length of the
spring.
Change the spring.
2. Setting of damping force
Change the rebound damping.
Change the compression damp-
ing.
CHOOSING SET LENGTH
1. Place a stand or block under the
engine to put the rear wheel
above the floor, and measure the
length "a" between the rear wheel
axle center and the rear fender
holding bolt.
2. Remove the stand or block from
the engine and with a rider astride
the seat, measure the sunken
length "b" between the rear wheel
axle center and the rear fender
holding bolt.
3. Loosen the locknut "1" and make
adjustment by turning the spring
adjuster "2" to achieve the stan-
dard figure from the subtraction of
the length "b" from the length "a".
If the machine is new and after it is
broken in, the same set length of
the spring may change because of
the initial fatigue, etc. of the spring.
Therefore, be sure to make reeval-
uation.
If the standard figure cannot be
achieved by adjusting the spring
adjuster and changing the spring
Standard oil amount:
333 cm
3
(11.72 Imp oz,
11.26 US oz)
*335 cm
3
(11.79 Imp oz,
11.33 US oz)
Extent of adjustment:
300–375 cm
3
(10.6–13.2
Imp oz, 10.1–12.7 US
oz)
* For EUROPE
TYPE
SPRI
NG
RATE
SPRING
PART
NUMBER
(-23141-)
I.D.
MARK
(slits)
SOFT
0.398 1C3-A1 |
0.408 1C3-B1 ||
STD 0.418 1C3-P0
STIFF
0.428 1C3-D1 ||||
0.438 1C3-E1 |||||
0.449 1C3-F1 |-|
0.459 1C3-G1 |-||
0.469 1C3-H1 |-|||
0.479 1C3-J1 |-||||
Standard figure:
90–100 mm (3.5–3.9 in)
7-8
CHASSIS
set length, replace the spring with
an optional one and make readjust-
ment.
SETTING OF SPRING AFTER
REPLACEMENT
After replacement, be sure to adjust
the spring to the set length [sunken
length 90–100 mm (3.5–3.9 in)] and
set it.
1. Use of soft spring
Set the soft spring for less re-
bound damping to compensate
for its less spring load. Run with
the rebound damping adjuster
one or two clicks on the softer
side and readjust it to suit your
preference.
2. Use of stiff spring
Set the soft spring for more re-
bound damping to compensate
for its greater spring load. Run
with the rebound damping adjust-
er one or two clicks on the stiffer
side and readjust it to suit your
preference.
Adjusting the rebound damping will
be followed more or less by a change
in the compression damping. For cor-
rection, turn the low compression
damping adjuster on the softer side.
When using a rear shock absorber
other than currently installed, use
the one whose overall length "a"
does not exceed the standard as it
may result in faulty performance.
Never use one whose overall
length is greater than standard.
REAR SHOCK ABSORBER
SETTING PARTS
Rear shock spring "1"
[Equal-pitch titanium spring]
[Equal-pitch steel spring]
[Unequal-pitch steel spring]
Install the spring seat "2" to the ti-
tanium spring.
The unequal-pitch spring is softer in
initial characteristic than the equal-
pitch spring and is difficult to bottom
out under full compression.
The I.D. mark "a" is marked at the
end of the spring.
Spring specification varies accord-
ing to the color and quantity of I.D.
marks.
Length "a" of standard
shock:
490 mm (19.29 in)
TYPE
SPRI
NG
RATE
SPRING
PART
NUM-
B ER
(-22212-)
I.D.
MARK
Green/1
SOFT 4.5 1C3-00 Green/2
Green/3
Red/1
STD 4.7 1C3-10 Red/2
Red/3
STIFF
Black/1
4.9 1C3-20 Black/2
Black/3
Blue/1
5.1 1C3-30 Blue/2
Blue/3
TYPE
SPRI
NG
RATE
SPRING
PART
NUM-
B ER
(-22212-)
I.D.
MARK/
Q'TY
SOFT 4.3 5UN-00 Brown/1
5.3 5UN-50 Yellow/1
STIFF
5.5 5UN-60 Pink/1
5.7 5UN-70 White/1
TYPE
SPRI
NG
RATE
(ap-
prox.)
SPRING
PART
NUM-
BER
(-22212-)
I.D.
MARK/
Q'TY
SOFT 4.5 5UN-A0 Green/2
4.7 5UN-B0 Red/2
4.9 5UN-C0 Black/2
5.1 5UN-D0 Blue/2
STIFF
5.3 5UN-E0 Yellow/2
5.5 5UN-F0 Pink/2
5.7 5UN-G0 White/2
7-9
CHASSIS
Extent of adjustment (spring pre-
load)
For the spring preload adjustment,
refer to "ADJUSTING THE REAR
SHOCK ABSORBER SPRING
PRELOAD" in the CHAPTER 3.
Preload adjusting extent is the
same for the titanium and steel
springs.
SPRING
PART
NUMBER
(-22212-)
Maximum Minimum
1C3-00
1C3-10
1C3-20
1C3-30
5UN-00
5UN-A0
5UN-B0
5UN-C0
5UN-D0
5UN-E0
5UN-F0
5UN-G0
Position
in which
the spring
is turned
in 18 mm
(0.71 in)
from its
free
length.
Position
in which
the spring
is turned
in 1.5 mm
(0.06 in)
from its
free
length.
5UN-50
5UN-60
5UN-70
Position
in which
the spring
is turned
in 20 mm
(0.79 in)
from its
free
length.
7-10
CHASSIS
SUSPENSION SETTING (FRONT FORK)
If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to
the adjustment procedure given in the same chart.
Before any change, set the rear shock absorber sunken length to the standard figure 90–100 mm (3.5–3.9 in).
Symptom
Section
Check Adjust
Jump
Large
gap
Medi-
um
gap
Small
gap
Stiff over entire
range
○○○
Compression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil amount Decrease oil amount by about 5–10 cm
3
(0.2–0.4 Imp oz, 0.2–0.3 US oz).
Spring Replace with soft spring.
Unsmooth move-
ment over entire
range
○○○○
Outer tube Check for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Inner tube
Slide metal Replace with a new one for extended use.
Piston metal Replace with a new one for extended use.
Under bracket tighten-
ing torque
Retighten to specified torque.
Poor initial move-
ment
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil seal Apply grease in oil seal wall.
Soft over entire
range, bottoming
out
○○
Compression damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Oil amount Increase oil amount by about 5–10 cm
3
(0.2–0.4 Imp oz, 0.2–0.3 US oz).
Spring Replace with stiff spring.
Stiff toward stroke
end
Oil amount
Decrease oil amount by about 5 cm
3
(0.2 Imp oz,0.2 US oz).
Soft toward stroke
end, bottoming out
Oil amount
Increase oil amount by about 5 cm
3
(0.2 Imp oz,0.2 US oz).
Stiff initial move-
ment
○○○○Compression damping
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front posture
○○
Compression damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Balance with rear end Set sunken length for 95–100 mm (3.7–3.9 in)
when one passenger is astride seat
(lower rear posture).
Oil amount Increase oil amount by about 5 cm
3
(0.2 Imp oz, 0.2 US oz).
"Obtrusive" front,
tending to upper
front posture
○○
Compression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Balance with rear end Set sunken length for 90–95 mm (3.5–3.7 in)
when one passenger is astride seat
(upper rear posture).
Spring Replace with soft spring.
Oil amount Decrease oil amount by about 5–10 cm
3
(0.2–0.4 Imp oz, 0.2–0.3 US oz).
7-11
CHASSIS
SUSPENSION SETTING (REAR SHOCK ABSORBER)
If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to
the adjustment procedure given in the same chart.
Adjust the rebound damping in 2-click increments or decrements.
Adjust the low compression damping in 1-click increments or decrements.
Adjust the high compression damping in 1/6 turn increments or decrements.
Symptom
Section
Check Adjust
Jump
Large
gap
Medi-
um
gap
Small
gap
Stiff, tending to sink ○○
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in)
when one passenger is astride seat.
Spongy and unsta-
ble
○○
Rebound damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Low compression
damping
Turn adjuster clockwise (about 1 click) to increase
damping.
Spring Replace with stiff spring.
Heavy and dragging ○○
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Spring Replace with soft spring.
Poor road gripping
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low compression
damping
Turn adjuster clockwise (about 1 clicks) to in-
crease damping.
High compression
damping
Turn adjuster clockwise (about 1/6 turn) to in-
crease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in)
when one passenger is astride seat.
Spring Replace with soft spring.
Bottoming out ○○
High compression
damping
Turn adjuster clockwise (about 1/6 turn) to in-
crease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in)
when one passenger is astride seat.
Spring Replace with stiff spring.
Bouncing ○○
Rebound damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Spring Replace with soft spring.
Stiff travel ○○
High compression
damping
Turn adjuster counterclockwise (about 1/6 turn) to
decrease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in)
when one passenger is astride seat.
Spring Replace with soft spring.
PRINTED IN JAPAN
(E)
PRINTED ON RECYCLED PAPER
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  • wie stelle ich den vergaser bei der 125 yz 2018 ein Eingereicht am 30-4-2018 19:56

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