8. CYLINDER HEAD/VALVES                                                       MXU 500 IRS

 TORQUE VALUES
 Cylinder head bolt (1 ­ 4)     4.8 kgf-m (48 N-m)              Apply engine oil to threads
 Cylinder head bolt (5 ­ 13)    2.3 kgf-m (23 N-m)              Apply engine oil to threads
 Cylinder head nut              1 kgf-m (10 N-m)
 Cylinder head cover bolt       1 kgf-m (10 N-m)
 Breather separator bolt        1.3 kgf-m (13 N-m)
 Cam chain tensioner bolt       1.2 kgf-m (12 N-m)
 Tensioner sealing bolt         1 kgf-m (10 N-m)
 Rocker arm shaft               4.5 kgf-m (45 N-m)
 Cam chain guide pivot bolt     2 kgf-m (20 N-m)
 Water joint bolt               1.2 kgf-m (12 N-m)




 SPECIAL TOOLS
 Valve spring compressor           A120E00040




 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 oil 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 tensioner
 · 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




8-3