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Repair manual KTM 250 / 300 / 380 Art No 3206004 -E
9-2C
Engine 250 SX 250 EXC, MXC 300 EXC, MXC 380 SX 380 EXC, MXC
Design Liquid-cooled single-cylinder two-stroke engine with KTM Twin Valve Control exhaust system and KTM Torque Chamber
Piston displacement 249 ccm 297 ccm 368 ccm
Bore / stroke 67.5 / 69.5 mm (2.66 / 2.74 in) 72 / 73 mm (2.84 / 2.88 in) 78 / 77 mm (3 / 2.98 in)
Fuel SUPER fuel, research octane no 95, mixed with high-grade two stroke oil (Shell Advance Racing X)
Oil / gasolin ratio 1:50 - 1:60 when using high grade two stroke oil. When in doupt, 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 cast piston
Piston ring two plain compression rings
Dimension "X"
0 mm
+0.1 mm
(0 in
+ 0.004 in
)
Ignition timing 1.8 mm (0.07 in) (17 °) BTDC 2.0 mm (0.08 in) (17°) BTDC 2.2 mm (0.09 in) (17 °) BTDC
Spark plug NGK BR 8 ECM
Electrode gap 0.6 mm (0.024 in)
Dimension "Z"
48 mm (1.9 in) 46 mm (1.7 in) 50.5 mm (1.99 in)
TVC start open 5400/min 5300/min 5200/min
TVC fully open 7550/min 7750/min 7200/min
Primary drive straight cut spur gears, primary ratio 25:72 straight cut spur gears, primary ratio 26:72
Clutch multiple disc clutch in oil bath, hydraulic operated (Shell HF-E15)
Transmission 5 speed, claw actuated
Gear ratio EXC M-XC EXC MXC
1
st
Gear 15:29 15:29 15:29 15:29 15:29 15:29 15:29
2
nd
Gear 17:27 18:26 18:26 18:26 18:26 18:26 18:26
3
rd
Gear 19.25 19:22 19:22 19:24 19:24 19:22 19:24
4
th
Gear 21:23 21:20 21:20 21:23 21:23 21:20 21:23
5
th
Gear 23:21 23:18 23:18 23:21 23:21 23:18 23:21
Gear lubrication 0.8 l engine oil 20W-40 (Shell Advance VSX4)
Available chain sprockets
13t / 14t / 15t for chain
5
/8 x
1
/4"
Coolant 1.3 litres, 40% anti freeze, 60% water, at least -25 °C (-13 °F)
Ignition system KOKUSAN 2K-1 KOKUSAN 2K-2 KOKUSAN 2K-1 KOKUSAN 2K-2
Generator output no generator 12V 40W no generator 12V 40W
Carburetor flat-slide carburetor, carburetor setting see table 3
Air-filter wet foam type air filter insert
(upper edge piston -
upper edge cylinder)
(height of the
control flap)
TECHNICAL SPECIFICATIONS - ENGINE 250/300/380 SX/MXC/EXC ‘99 (only for USA)