Troubleshooting
0-23
that will dissolve the adhesive bonding the carbon particles to the
piston crowns and chambers is the easiest way to remove the build-
up. Otherwise, the cylinder heads will have to be removed and
decarbonized (Chapter 2).
20 Firing incorrect
1 Spark plug fouled, defective or worn out. See Chapter 1 for spark
plug maintenance.
2 Incorrect spark plug (see Chapter 1).
3 Faulty ignition coil(s) (Chapter 4).
21 Fuel/air mixture incorrect
1 Main jet clogged. Dirt, water and other contaminants can clog the
main jets. Clean the fuel tap filter, the float bowl area and the jets and
carburetor orifices (Chapter 3).
2 Main jet wrong size. The standard jetting is for sea level
atmospheric pressure and oxygen content.
3 Air cleaner poorly sealed or missing.
4 Air cleaner-to-carburetor boot poorly sealed. Look for cracks,
holes or loose clamps and replace or repair.
5 Fuel level too low. Adjust the float(s) (Chapter 3).
6 Fuel tank air vent obstructed. Make sure that the air vent passage
in the filler cap is open.
7 Carburetor intake joints loose. Check for cracks, breaks, tears or
loose clamps or bolts. Repair or replace the rubber boots (Chapter 3).
22 Compression too high
1 Carbon build-up in combustion chamber. Use of a fuel additive
that will dissolve the adhesive bonding the carbon particles to the
piston crown and chamber is the easiest way to remove the build-up.
Otherwise, the cylinder head will have to be removed and
decarbonized (Chapter 2).
2 Improperly machined head surface or installation of incorrect
gasket during engine assembly.
23 Engine load excessive
1 Clutch slipping. Can be caused by damaged, loose or worn clutch
oonents. Refer to Chapter 2 for overhaul procedures.
Engine oil level too high. The addition of too much oil will cause
pressurization of the crankcase and inefficient engine operation. Check
Specifications and drain to proper level (Chapter 1).
3 Engine oil viscosity too high. Using a heavier oil than the one
r
ecommended in Chapter 1 can damage the oil pump or lubrication
system as well as cause drag on the engine.
4 Brakes dragging. Usually caused by debris which has entered the
brake piston sealing boot, or from a warped disc or bent axle. Repair
as necessary.
24 Lubrication inadequate
1 Engine oil level too low. Friction caused by intermittent lack of
lubrication or from oil that is overworked can cause overheating. The
oil provides a definite cooling function in the engine. Check the oil level
(Chapter 1).
2 Poor quality engine oil or incorrect viscosity or type. Oil is rated
not only according to viscosity but also according to type. Some oils
are not rated high enough for use in this engine. Check the Specifi-
cations section and change to the correct oil (Chapter 1).
3 Camshaft or journals worn. Excessive wear causing drop in oil
pressure. Replace cam, bushing or cylinder head. Abnormal wear
could be caused by oil starvation at high rpm from low oil level or
improper viscosity or type of oil (Chapter 1).
4 Crankshaft and/or bearings worn. Same problems as para-
graph 3. Check and replace crankshaft and/or bearings (Chapter 2).
25 Miscellaneous causes
Modification to exhaust system. Most aftermarket exhaust
systems cause the engine to run leaner, which make them run hotter.
When installing an accessory exhaust system, always rejet the
carburetors.
Clutch problems
26 Clutch slipping
1 Friction plates worn or warped. Overhaul the clutch assembly
(Chapter 2).
2 Steel plates worn or warped (Chapter 2).
3 Clutch spring(s) broken or weak. Old or heat-damaged spring(s)
(from slipping clutch) should be replaced with new ones (Chapter 2).
4 Clutch release mechanism defective. Replace any defective parts
(Chapter 2).
5 Clutch boss or housing unevenly worn. This causes improper
engagement of the plates. Replace the damaged or worn parts
(Chapter 2).
27 Clutch not disengaging completely
1 Clutch lever play excessive (see Chapter 1). Clutch cable
improperly adjusted (see Chapter 1).
2 Clutch plates warped or damaged. This will cause clutch drag,
which in turn will cause the machine to creep. Overhaul the clutch
assembly (Chapter 2).
3 Usually caused by a sagged or broken spring(s). Check and
replace the spring(s) (Chapter 2).
4 Engine oil deteriorated. Old, thin, worn out oil will not provide
proper lubrication for the discs, causing the clutch to drag. Replace the
oil and filter (Chapter 1).
5 Engine oil viscosity too high. Using a thicker oil than
recommended in Chapter 1 can cause the plates to stick together,
putting a drag on the engine. Change to the correct viscosity oil
(Chapter 1).
6 Clutch housing seized on shaft. Lack of lubrication, severe wear
or damage can cause the housing to seize on the shaft. Overhaul of the
clutch, and perhaps transmission, may be necessary to repair the
damage (Chapter 2).
7 Clutch release mechanism defective. Worn or damaged release
mechanism parts can stick and fail to apply force to the pressure plate.
Overhaul the release mechanism (Chapter 2).
8 Loose clutch boss nut. Causes housing and boss misalignment
putting a drag on the engine. Engagement adjustment continually
varies. Overhaul the clutch assembly (Chapter 2).
Gear shifting problems
28 Doesn't go into gear or lever doesn't return
1- Clutch not disengaging. See Section 27.
2 Shift fork(s) bent or seized. Often caused by dropping the
machine or from lack of lubrication. Overhaul the transmission
(Chapter 2).
