Kymco MO P125, MO P 150 Service Manual - chap 07 (testa e valv)
7. CYLINDER HEAD/VALVES
7-0
PEO PLE 12 5/ 15 0
7
CYLINDER HEAD/VALVES
SERVICE INFORMATION..........................................................7-2
TROUBLESHOOTING ................................................................7-3
CAMSHAFT REMOVAL.............................................................7-4
CYLINDER HEAD REMOVAL....................................................7-7
CYLINDER HEAD DISASSEMBLY.............................................7-8
CYLINDER HEAD ASSEMBLY................................................. 7-10
CYLINDER HEAD INSTALLATION .........................................7-10
CAMSHAFT INSTALLATION................................................... 7-11
7
7. CYLINDER HEAD/VALVES
7-1
PEO PLE 125/150
0.8kg-m
1.2kg-m
2.0kg-m
7. CYLINDER HEAD/VALVES
7-2
PEO PLE 125/150
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• The cylinder head can be serviced with the engine installed in the frame.
• When assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable
parts, valve arm and camshaft sliding surface for initial lubrication.
• The camshaft is lubricated by engine oil through the cylinder head engine oil passages. Clean the
oil passages before assembling the cylinder head.
• After disassembly, clean the removed parts and dry them with compressed air before inspection.
• After removal, mark and arrange the removed parts in order. When assembling, install them in the
reverse order of removal.
SPECIFICATIONS
Standard (mm)
Service Limit (mm)
Item
125cc
150cc
125cc
150cc
IN
0.10
0.10
－
－
Valve clearance (cold)
EX
0.10
0.10
－
－
Cylinder head compression pressure
13 (kg/cm_)
15 (kg/cm_)
－
－
Cylinder head warpage
－－－
－
IN
29.7064
29.803
29.3
29.4
Camshaft cam height
EX
29.4251
29.4388
29.15
29.05
IN
10.000-10.015
10.10
Valve rocker arm I.D.
EX
10.00-10.015
10.10
IN
9.972-9.987
9.91
Valve rocker arm shaft
O.D.
EX
9.972-9.987
9.91
IN
1.0
1.8
Valve seat width
EX
1.0
1.8
IN
4.975-4.990
4.90
Valve stem O.D.
EX
4.975-4.990
4.90
IN
5.000-5.012
5.30
Valve guide I.D.
EX
5.000-5.012
5.30
IN
0.10-0.037
0.08
Valve stem-to-guide
clearance
EX
0.030-0.057
0.10
7. CYLINDER HEAD/VALVES
7-3
PEO PLE 125/150
TORQUE VALUES
Cylinder head nut 2.0kg-m Apply engine oil to threads
Valve clearance adjusting nut 0.8kg-m Apply engine oil to threads
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 valve seat contact • Worn cam chain guide
• Leaking cylinder head gasket • Worn camshaft and rocker arm
• Warped or cracked cylinder head contact surface
• Poorly installed spark plug
Compression too high
• Excessive carbon build-up in combustion
chamber
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