Service Information; Troubleshooting - Honda CBR650RA Shop Manual

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CYLINDER HEAD/VALVES

SERVICE INFORMATION

CYLINDER HEAD/VALVES
GENERAL
• This section covers service of the cylinder head, valves and camshafts.
• All the services covered in this section can be done with the engine installed in the frame.
• When disassembling, mark and store the disassembled parts to ensure that they are reinstalled in their original locations.
• Clean all disassembled parts with cleaning solvent and dry them by blowing them off with compressed air before inspection.
• Camshafts lubricating oil is fed through oil passages in the cylinder head and camshaft holder. Clean the oil passages before
assembling them.
• Be careful not to damage the mating surfaces when removing the cylinder head cover and cylinder head.

TROUBLESHOOTING

• Engine top-end problems usually affect engine performance. These problem can be diagnosed by a compression test or by
tracing engine noises to the top-end with a sounding rod stethoscope.
• If the performance is poor at low speeds, check for white smoke in the crankcase breather hose. If the hose is smoky, check for
a seized piston ring (page 14-14).
Compression too low, hard starting or poor performance at low speed
• Valves:
– Incorrect valve clearance adjustment
– Burned or bent valve
– Incorrect valve timing
– Broken valve spring
– Uneven valve seating
• Cylinder head:
– Leaking or damaged cylinder head gasket
– Warped or cracked cylinder head
– Loose spark plug
• Worn cylinder, piston or piston rings (page 14-14)
Compression too high, overheating or knocking
• Excessive carbon build-up on piston crown or on combustion chamber
Excessive smoke
• Cylinder head:
– Worn valve stem or valve guide
– Damaged stem seal
• Worn cylinder, piston or piston rings (page 14-14)
Excessive noise
• Cylinder head:
– Incorrect valve clearance adjustment
– Sticking valve or broken valve spring
– Damaged or worn camshaft
– Loose or worn cam chain
– Worn or damaged cam chain
– Worn or damaged cam chain tensioner
– Worn cam sprocket teeth
• Worn cylinder, piston or piston rings (page 14-14)
Rough idle
• Low cylinder compression
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