1986-1989 Honda TRX250 FourTrax 250R Service Manual, Page 61Get this manual
CYLINDER HEADCYLINDERPISTON
TROUBLESHOOTI NG
Compression too low, hard starting or poor performance at low speed Blown cylinder head gasket Loose spark plug Worn, stuck or broken piston rings Worn or damaged cylinder and piston Faulty reed va lve Worn crankshaft sea ls Compression too high, overheating or knocking Excessive carbon buildup in combustion chamber or on piston head Abnormal noisepiston Worn or cracked piston Worn cylinder and piston Worn piston pin or piston pin hole Worn connecting rod small end bearing Abnormal noisepiston rings Worn, stuck or broken piston rings Worn or damaged cylinder Contaminated coolant Leaking head gasket