9-37C
Repair manual KTM 250 / 300 / 380 Art No 3206004 -E
Engine 250 MXC/EXC 300 MXC/EXC
Desgin Liquid-cooled single-cylinder two-stroke engine with KTM Twin Valve Control exhaust system and KTM Torque Chamber
Piston displacement 249 ccm 297 ccm
Bore / stroke 66,4 / 72 mm (2.62 / 2.84 in) 72 / 73 mm (2.84 / 2.88 in)
Fuel unleaded SUPER fuel, research octane no 95, mixed with high-grade, two- stroke oil
Oil / gasolino ratio 1:40 – 1:60 when using high grade, two- stroke oil. When in dout, please contact your importer or use 1:40 mix ratio to be on the safe side
Crankshaft bearing 1 deep-groove ball bearing / 1 cylinder roller bearing
Connecting rod bearing needle bearing
Piston pin bearing needle bearing
Piston cast piston forged piston
Piston ring two plain compression rings
Dimension “X“
0 + 0,1 mm (0 + 0.004 in)
Ingition timing 1,9 mm vor OT 1,94 mm vor OT
Spark plug NGK BR 7 ES
Electrode gap 0,60 mm
Dimension “Z“
49,5 mm (0.024 in) 46 mm (1.7 in)
TVC start open 5000/min 5900/min
TVC fully open 7000/min 7750/min
Primary drive straight cut spur gears, primary ratio 25:72
Clutch multiple disc clutch in oil bath, hydraulically operated (Shell HF-E15
Transmission 5 speed, claw actuated
Gear ratio EXC MXC EXC MXC
1
st
gear 15:29 15:29 15:29 15:29
2
nd
gear 18:26 17:27 18:26 18:26
3
rd
gear 19:22 19:25 19:22 19:24
4
th
gear 21:20 21:23 21:20 21:23
5
th
gear 23:18 23:21 23:18 23:21
Gear lubrication 0,8 l engine oil 10W-40
ailable chain sprockets 13Z / 14Z / 15Z for chain
5
/
8
x
1
/
4
"
Coolant 1.3 liters, 40% antifreeze, 60% water, at least -25 °C (-13 °F)
Ignition system KOKUSAN 2K-3
Generator output 12V 110W
Ignition system USA (MXC) KOKUSAN 2K-2
Generator output 12V 40W
Carburetor flat-slide carburetor, carburetor setting see table
Air- filter wet foam type air filter insert
(upper edge piston -
upper edge cylinder)
(height of the
control flap)
TECHNICAL DATA - ENGINE 250/300 MXC / EXC 2003
