KYMCO MX 125 - Cylinder Head;Valves; Service Information

7. CYLINDER HEAD/VALVES
7-2
MX’er SYSTEM
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 surfaces for initial lubrication.
• The camshaft is lubricated by engine oil through the cylinder head engine oil passages. Clean and
unclog 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
Item Standard (mm) Service Limit (mm)
IN 0.06 ⎯
EX 0.06 ⎯
Cylinder head compression pressure 16kg/cm²
Cylinder head warpage ⎯ 0.05
IN 31.8 31.4
EX 31.53 31.13
Valve rocker arm to shaft clearance
0.090.034 0.1
Valve stem-to-guide IN 0.0100.037 0.06
clearance
EX 0.0250.052 0.08
IN 39.4 ⎯
Valve spring free length
EX 45.5 ⎯
IN 7.78.9kg(at 33.7mm) ⎯
Valve spring
compressed force
EX 19.522.5kg(at 38.4mm) ⎯
IN 1.7 ⎯
Valve spring tilt
EX 1.95 ⎯
Valve clearance (cold)
Camshaft cam height