ENGLISH
54
ENGINE
250 SX
250 EXC
300 XC/EXC
Design
Liquid-cooled single-cylinder two-stroke engine
with KTM Twin Valve Control exhaust system and KTM Torque Chamber
Piston displacement
249 ccm
249 ccm
293.15 ccm
Bore / stroke
66.4 / 72 mm (2.62 / 2.84 in)
66.4 / 72 mm (2.62 / 2.84 in) 72 / 72 mm (2.84 / 2.84 in)
Fuel
unleaded fuel with at least RON 95 (USA = Premium RON 91), mixed with high grade two stroke oil (Motorex Cross Power 2T)
Oil / gasoline ratio
1:40 – 1:60 when using high grade, two- stroke oil.
When in doubt, 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
Piston ring
two plain compression rings
two plain compression rings
two plain compression rings
Dimension „X“
0 + 0,1 mm (0 + 0.004 in)
Ignition timing
1,9 mm (0.074 in) BTDC
Spark plug
NGK BR8 ECM
NGK BR7 ES
NGK BR 7 ES
Electrode gap
0,60 mm
Dimension „Z“
47,5 mm (1.87 in)
TVC start open
5200/min
TVC fully open
7000/min (red spring), 7500/min (yellow spring), 7900/min (green spring)
Primary drive
straight cut spur gears, primary ratio 26:72
Clutch
multiple disc clutch in oil bath, hydraulically operated (DOT 5.1)
Transmission
5 speed, claw actuated
Gear ratio
250 SX
250/300 EXC, XC-W
250/300 XC
1st gear
14 : 28
14 : 30
14 : 28
2nd gear
15 : 24
17 : 26
15 : 24
3rd gear
18 : 24
19 : 23
18 : 24
4th gear
21 : 24
20 : 20
21 : 24
5th gear
22 : 21
29 : 23
22 : 21
Gear lubrication
0,7 liter Motorex Top Speed 4T 15W50
Available chain sprockets
13t / 14t for chain 5/8 x 1/4"
Coolant
1.2 litres, 50% anti freeze, 50% distilled water, at least -25 °C (-13 °F)
Ignition system
KOKUSAN 2K-1
KOKUSAN 2K-3
KOKUSAN 2K-3
Generator output
no generator
12V / 110 W
12V / 110 W
Ignition system XC-W
–
KOKUSAN 2K-2 (XC, XC-W)
KOKUSAN 2K-2 (XC, XC-W)
Generator output
–
12V 40 W
12V 40 W
Vergaser
flat-slide carburetor, carburetor setting see table
Air-filter
wet foam type air filter insert
TECHNICAL SPECIFICATIONS – ENGINE 250 SX, EXC, 300 XC, EXC
»
(upper edge piston-
upper edge cylinder)
(height of the control flap)