Repair manual KTM 250 / 300 / 380 Art No 3206004 -E
9-10C
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 66.4 / 72 mm (2.62 / 2.84 in) 72 / 73 mm (2.84 / 2.88 in) 78 / 77 mm (3 / 2.98 in)
Fuel unleaded SUPER fuel, research octane no 95, mixed with high-grade two stroke oil (Shell Advance Racing X)
Oil / gasolin ratio 1:40 – 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 one plain compression rings two plain compression rings
Dimension "X"
0 +0.1 mm (0 + 0.004 in)
Ignition timing 2.0 mm (0.07 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"
50,5 mm (1.99 in) 46 mm (1.7 in) 50.5 mm (1.99 in)
TVC start open 5000/min 5300/min 5200/min
TVC fully open 7500/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 MXC EXC MXC EXC MXC
1
st
Gear 15:29 15:29 15:29 15:29 15:29 15:29 15:29 15:29
2
nd
Gear 17:27 18:26 17:27 18:26 18:26 18:26 18:26 18:26
3
rd
Gear 19:25 19:22 19:25 19:22 19:24 19:24 19:22 19:24
4
th
Gear 21:23 21:20 21:23 21:20 21:23 21:23 21:20 21:23
5
th
Gear 23:21 23:18 23:21 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-4 KOKUSAN 2K-2 KOKUSAN 2K-1 KOKUSAN 2K-3
Generator output no generator 12V 40W no generator 12V 110W
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 250/300/380 SX / MXC / EXC 2000 (only USA)
