Troubleshooting - Honda CRF450R 2009 Service Manual

CYLINDER/PISTON
TROUBLESHOOTING
Engine lop-end problems usually affect engine performance. These problems can
be
diagnosed by a compression test or
by
tracing engine noise to Ihe top-end with a sounding rod stethoscope.
If Ihe pertormance is poor allow speeds. check for white smoke in the crankcase and cylinder head breather hose. If the hose is
smoky, check for a seized piston rings.
Compression too low, hard starting or poor performance at low speeds
leaking or damaged cylinder head gasket
Worn , stuck or broken piston rings
• Worn or damaged cylinder and piston
• loose spark
plug
Compression too high, over.heating or knocking
• Excessive carbon build-up in on piston head or combustion chamber
Abnormal noise
Worn cylinder and piston
Worn piston pin or piston pin hole
• Worn connecting rod small end
• Worn connecting rod big end bearing (page 13-22)
Excessive smoke
Faulty cylinder, piston and piston rings
Improper installation of piston rings
• Scored or scratched piston or cylinder wall
10-4