KTM 300 MXC User Manual

ENGINE 250 SX 250 EXC 300 MXC/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“ 48,5 mm (1.9 in) - 0,2 mm (0,008 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 (Motorex Kupplungs- Fluid 75)
Transmission 5 speed, claw actuated
Gear ratio 250 SX 250/300 EXC 300 MXC
1st gear 14 : 28 14 : 30 14 : 28
2nd gear 16 : 26 17 : 26 16 : 26
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% 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 USA KOKUSAN 2K-1 KOKUSAN 2K-2 KOKUSAN 2K-2
Generator output no generator 12V 40 W 12V 40 W
Vergaser flat-slide carburetor, carburetor setting see table
Air-filter wet foam type air filter insert
ENGLISH
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TECHNICAL SPECIFICATIONS – ENGINE 250 SX, EXC, 300 MXC, EXC »
(upper edge piston-
upper edge cylinder)
(height of the control flap)

KTM 300 MXC Specifications

General

Starter	Kickstarter
Bore x Stroke	72 mm x 72 mm
Fuel System	Carburetor
Rear Suspension	WP monoshock
Front Brake	Single 260mm disc
Rear Brake	Single 220mm disc
Fuel Tank Capacity	9.5 liters
Frame	Chromium-Molybdenum steel