KTM 250 EXC RACING - Manual (Page 53)

ENGLISH
52
Type 250 EXC 450 SX 450 MXC 450 EXC 525 SX 525 MXC 525 EXC
Design Liquid-cooled single cylinder 4-stroke engine with balancer shaft
Displacement 250 cc 449 cc 448 cc 510 cc
Bore/Stroke 75 / 56.5 mm 95 / 63.4 mm 89 / 72 mm 95 / 72 mm
Ratio 12 : 1 11 : 1
Fuel unleaded premium gasoline with at least RON 95
Valve timing 4 valves over rocker arm and 1 overhead camshaft, camshaft drive through single chain
Camshaft 5532 594/55 590/5521 8/06 590/5521
Valve diameter Intake 28 mm 35 mm (Titan) 35 mm
Valve diameter Exhaust 24 mm 30 mm (Titan) 30 mm
Valve clearence cold Intake 0.12 mm (0.0047 in)
Valve clearence cold Exhaust 0.12 mm (0.0047 in)
Crank shaft bearing 2 cylinder roller bearing
Connecting rod bearing needle bearing
Top end bearing bronze bushing
Piston alluminium alloy cast alluminium alloy forged
Piston rings 1 compression ring, 1 oil scraper ring
Engine lubrication pressure circulation lubrication with two rotor pumps
Engine oil full synthetic oil (Shell Advance Ultra 4 SAE 10W40)
Quantity of engine oil 1.25 liters
Primary ratio straight geared spur wheels 33:76 Z
Clutch multi disc clutch in oil bath
Transmission claw shifted 6-speed 4-speed 6-speed 6-speed 4-speed 6-speed 6-speed
Gear ratio
1
st Gear 14:38 16:32 16:32 14:34 16:32 16:32 14:34
2 nd Gear 16:36 18:30 18:30 17:31 18:30 18:30 17:31
3 rd Gear 19:34 20:28 20:28 19:28 20:28 20:28 19:28
4 th Gear 21:32 22:26 22:26 22:26 22:26 22:26 22:26
5 th Gear 23:30 - 24:24 24:23 - 24:24 24:23
6 th Gear 22:25 - 21:18 26:21 - 21:18 26:21
Ignition system contactless DC-CDI ignition with digital advanced system by KOKUSAN
Generator 12V 150W 12V 40W 12V 150W 12V 40W 12V 150W
Spark plug NGK DCPR 8 E
Spark plug gap 0.6 mm (0.02367 in)
Cooling system liquid cooled, permanent rotation of cooling liquid through mechanically driven water pump
Cooling liquid 1 liter, 40% antifreeze, 60% water, at least -25° (-13° F)
Starting equipment kick-electric starter kickstarter kick - electric starter kickstarter kick - electric starter
TECHNICAL DATA – ENGINE 250/450/525 SX, MXC, EXC RACING 2003