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8. CYLINDER HEAD/VALVES MXU 550EXi /MXU500i
SERVICE INFORMATION
GENERAL INSTRUCTIONS
· The cylinder head can be serviced with the engine installed in the frame. Coolant in the radiator
and water jacket must be drained first.
· When assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable
parts and valve arm sliding surfaces for initial lubrication.
· The 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.
· 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 Unit: mm
Item Standard Service Limit
IN 0.1 mm
Valve clearance (cold)
EX 0.1 mm
Cylinder head compression pressure 15 kg/cm2
Cylinder head warpage 0.05
Camshaft runout 0.05
IN 37.2614 37.11
Camshaft cam height
EX 37.0084 36.86
IN 10 10.015 10.1
Valve rocker arm I.D.
EX 10 10.015 10.1
Valve rocker arm shaft IN 9.975 9.99 9.9
O.D. EX 9.9759.99 9.9
Rocker arm to shaft clearance 0.009 0.042 0.1
IN 4.975 4.99 4.925
Valve stem O.D.
EX 4.955 4.97 4.915
IN 5 5.015 5.03
Valve guide I.D.
EX 5 5.015 5.03
Valve stem-to-guide IN 0.01 0.037 0.08
clearance EX 0.03 0.057 0.1
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