Troubleshooting - KYMCO UXV 500i Service Manual

8. CYLINDER HEAD/VALVES
TORQUE VALUES
Cylinder head bolt (1 – 4)
Cylinder head bolt (5 – 13)
Cylinder head nut
Cylinder head cover bolt
Breather separator bolt
Cam chain tensioner bolt
Tensioner sealing bolt
Rocker arm shaft
Cam chain guide pivot bolt
Water joint bolt
SPECIAL TOOLS
Valve spring compressor

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
• Compression too low
Compression too low
• Incorrect valve clearance adjustment
• Burned or bend valves
• Incorrect valve timing
• Broken valve spring
• Poor valve and seat contact
• Leaking cylinder head gasket
• Warped or cracked cylinder head
• Poorly installed spark plug
Compression too high
• Excessive carbon build-up in combustion
chamber
8-3
4.8 kgf-m (48 N-m, 35 lbf-ft)
2.3 kgf-m (23 N-m, 17 lbf-ft)
1 kgf-m (10 N-m, 7 lbf-ft)
1 kgf-m (10 N-m, 7.2 lbf-ft)
1.3 kgf-m (13 N-m, 9 lbf-ft)
1.2 kgf-m (12 N-m, 8.6 lbf-ft)
1 kgf-m (10 N-m, 7 lbf-ft)
4.5 kgf-m (45 N-m, 32 lbf-ft)
2 kgf-m (20 N-m, 15 lbf-ft)
1.2 kgf-m (12 N-m, 8.6 lbf-ft)
A120E00040
White smoke from exhaust muffler
• Worn valve stem or valve guide
• Damaged valve stem oil seal
Abnormal noise
• Incorrect valve clearance adjustment
• Sticking valve or broken valve spring
• Damaged or worn camshaft
• Worn cam chain tensioner
• Worn camshaft and rocker arm
Apply engine oil to threads
Apply engine oil to threads
UXV 500