KYMCO Kymco UXV 500i, Service Manual

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8. CYLINDER HEAD/VALVES
8-3
UXV 500
TORQUE VALUES
Cylinder head bolt (1 – 4) 4.8 kgf-m (48 N-m, 35 lbf-ft) Apply engine oil to threads
Cylinder head bolt (5 – 13) 2.3 kgf-m (23 N-m, 17 lbf-ft) Apply engine oil to threads
Cylinder head nut 1 kgf-m (10 N-m, 7 lbf-ft)
Cylinder head cover bolt 1 kgf-m (10 N-m, 7.2 lbf-ft)
Breather separator bolt 1.3 kgf-m (13 N-m, 9 lbf-ft)
Cam chain tensioner bolt 1.2 kgf-m (12 N-m, 8.6 lbf-ft)
Tensioner sealing bolt 1 kgf-m (10 N-m, 7 lbf-ft)
Rocker arm shaft 4.5 kgf-m (45 N-m, 32 lbf-ft)
Cam chain guide pivot bolt 2 kgf-m (20 N-m, 15 lbf-ft)
Water joint bol
t
1.2 kgf-m (12 N-m, 8.6 lbf-ft)
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