1985-1986 Honda ATC250R Shop Manual, Page 233Get this manual
TROUBLESHOOTING
ENGINE LACKS POWER
CHECK 1Raise rear wheels off ground and spin by hand WHEEL SPINS FREELY SYMPTOM PROBABLE CAUSE WHEEL DOES NOT SPIN-(1) Brake dragging FREELY (2) Worn or damaged wheel bearing (3) Wheel bearing not lubricated properly (4) Drive chain too tight (5) Rear axle nut excessively tightened TIRE PRESSURE IS TOO-j(1) Punctured tire LOW (2) Faulty tire valve
2Check tire pressure with tire gauge PRESSURE NORMAL 3Check clutch slipping
CLUTCH SLIPS- (1) (2) (3) (4)
Clutch spring weak Worn clutch discplate Warped clutch discplate Faulty clutch lifter
CLUTCH ENGAGED PROPERLY 4Lightly accelerate engine ENGINE SPEED INCREASED ENGINE SPEED DOES NOT(INCREASE SUFFICIENTLY (2) (3) (4) Clogged air cleaner Restricted fuel flow Clogged fuel tank breather tube Clogged muffler