2007-2009 Honda TRX300EX TRX300X service manual, Page 116Get this manual
CYLINDER HEADNALVE
TROUBLESHOOTING
Engine top-end problems usually affect engine performanceThese problems can be diagnosed by compression test, or by tracing top-end noise with sounding rod or stethoscope If the performance is poor at low speeds, check for white smoke in the crankcase breather hoseIf the hose is smoky, check for seized piston ring (page 8-5)Compression too low, hard starting or poor performance at low speed ValvesIncorrect valve adjustmentBurned or bent valveIncorrect valve timingWeak valve springUneven valve seatingValve stuck open Cylinder headLeaking or damaged cylinder head gasketWarped or cracked cylinder headLoose spark plug Cylinderpiston problem (page 8-3) Compression too high Excessive carbon build-up on piston head or combustion chamber Worn or damaged decompressor system Excessive smoke Worn valve stem or valve guide Damaged stem seal Cylinderpiston problem (page 8-3) Excessive noise Incorrect valve adjustment Sticking valve or broken valve spring Excessive worn valve seat Worn or damaged camshaft Worn rocker arm andor shaft Worn rocker arm follower and valve stem end Worn cam sprocket teeth Worn cam chain Worn or damaged cam chain tensioner Cylinderpiston problem (page 8-3) Rough idle Low cylinder compression