KYMCO MXU 500 - Service Information

8. CYLINDER HEAD/VALVES
8-2
MXU 500
SERVICE INFORMATION
GENERAL INSTRUCTIONS
xThe cylinder head can be serviced with the engine installed in the frame. Coolant in the radiator
and water jacket must be drained first.
xWhen assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable
parts and valve arm sliding surfaces for initial lubrication.
xThe valve rocker arms are lubricated by engine oil through the cylinder head engine oil passages.
Clean and unclog the oil passages before assembling the cylinder head.
xAfter disassembly, clean the removed parts and dry them with compressed air before inspection.
xAfter removal, mark and arrange the removed parts in order. When assembling, install them in
the reverse order of removal.
SPECIFICATIONS Unit: mm (in)
Item Standard Service Limit
IN 0.1 mm (0.004 in) 
Valve clearance (cold)
EX 0.1 mm (0.004 in) 
Cylinder head compression pressure 15 kg/cm
2
(1500 kPa, 213 psi) 
Cylinder head warpage  0.05 (0.002)
Camshaft runout  0.05 (0.002)
IN 37.2614 (1.4905) 37.11 (1.4844)
Camshaft cam height
EX 37.0084 (1.4803) 36.86 (1.4744)
IN 10 (0.4)阡10.015 (0.4006) 10.1 (0.404)
Valve rocker arm I.D.
EX 10 (0.4)阡10.015 (0.4006) 10.1 (0.404)
Valve rocker arm shaft IN 9.975 (0.399)阡9.99 (0.3996) 9.9 (0.396)
O.D. EX 9.975 (0.399)阡9.99 (0.3996) 9.9 (0.396)
Rocker arm to shaft clearance
0.009 (0.0004)阡0.042 (0.0017) 0.1 (0.004)
IN 4.975 (0.199)阡4.99 (0.1996) 4.925 (0.197)
Valve stem O.D.
EX 4.955 (0.1982)阡4.97 (0.1988) 4.915 (0.1966)
IN 5 (0.2)阡5.015 (0.2006) 5.03 (0.2012)
Valve guide I.D.
EX 5 (0.2)阡5.015 (0.2006) 5.03 (0.2012)
Valve stem-to-guide IN 0.01 (0.004)阡0.037 (0.0015) 0.08 (0.0032)
clearance EX 0.03 (0.0012)阡0.057 (0.0023) 0.1 (0.004)