kxr 50 90 Workshop-manual : Page 104

          7. CYLINDER HEAD/VALVES
   (Mongoose/KXR 90)                                                  Mongoose/KXR 90/50


 TORQUE VALUES
 Cylinder head cover bolt        0.81.2kgf-m
 Cam shaft hold nut              1.82.2kgf-m                    Apply engine oil to threads
 Tappet adjusting nut            0.71.1kgf-m


 SPECIAL TOOLS
 Valve spring compressor           E040
 Tappet adjuster                   E036




 TROUBLESHOOTING
 · The poor cylinder head operation can be diagnosed by a compression test or by tracing engine
   top-end noises.

 Poor performance at idle speed                      White smoke from exhaust muffler
 · Compression too low                               · Worn valve stem or valve guide
                                                     · Damaged valve stem seal
 Compression too low
 · Incorrect valve clearance adjustment              Abnormal noise
 · Burned or bend valves                             · Incorrect valve clearance adjustment
 · Incorrect valve timing                            · Sticking valve or broken valve spring
 · Broken valve spring                               · Damaged or worn camshaft
 · Poor valve and seat contact                       · Worn cam chain guide
 · Leaking cylinder head gasket                      · Worn camshaft and rocker arm
 · Warped or cracked cylinder head
 · Poorly installed spark plug

 Compression too high
 · Excessive carbon build-up in combustion
   chamber




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