KTM 450 SX - Manual (Page 55)

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TECHNICAL DATA – ENGINE
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ENGINE 250 SX-F
Design Liquid-cooled single cylinder 4-stroke engine
Displacement 249.51 ccm
Bore/Stroke 76 / 55 mm
Ratio 12.8 : 1
Fuel unleaded fuel with at least RON 95
Valve timing 4 valves controlled by finger levers and 2 camshafts,
driven by a pair of spur gears and a tooth-type chain
Camshaft 05
Valve diameter Intake 30.9 mm
Valve diameter Exhaust 26.5 mm
Valve clearence cold Intake 0.10 - 0.20 mm (0.004 - 0.008 in)
Valve clearence cold Exhaust 0.12 - 0.22 mm (0.005 - 0.009 in)
Crank shaft bearing
2 cylinder roller bearings
Connecting rod bearing needle bearing
Top end bearing bronze bushing
Piston alluminium alloy forged
Piston rings 1 compression ring, 1 oil scraper ring
Engine lubrication pressure circulation lubrication with 2 rotor pumps
Engine oil full synthetic oil (Motorex Power Synt 4T 10W/50)
Quantity of engine oil 1.1 liters
Primary drive 22:68
Transmission claw shifted 6-speed
1st gear 13:32
2nd gear 15:30
3rd gear 17:28
4th gear 19:26
5th gear 21:25
6th gear 22:24
Ignition system contactless DC-CDI ignition with digital advanced system by KOKUSAN
Generator no generator
Spark plug NGK CR 9 EBK
Cooling system liquid cooled, permanent rotation of cooling liquid through mechanically driven water pump
Cooling liquid 1.2 liters, 50% antifreeze, 50% destilled water, at least -25° (-13° F)
Engine oil
Only use fully synthetic engine oils that meet the JASO MA quality require-
ments (see information on the can).
KTM recommends Motorex Power Synt 4T in the 10W/50 viscosity (for tem-
peratures over 0°C, 32°F) or 5W/40 (for temperatures under 0°C, 32°F).
POOR OIL QUALITY OR MINOR QUANTITY CAUSE EARLY ENGINE-WEAR.
0°C
32°F
10W/50 5W/40
JASO T903 MA
TEMPERATUR