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8. CYLINDER HEAD/VALVES MXU 550EXi /MXU500i
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