CF MOTO CF500-5, Service Manual

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6 Engine Removal,Inspection & Installation
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Cylinder Head Distortion
Clean off carbon deposit from combustion chamber;
Check the gasket surface of the cylinder head for
distortion with a straightedge and thickness gauge.
Take clearance readings from several places. If any
clearance reading is out of the service limit, replace
with a new cylinder head.
Valve Seat Width
Coat the valve seat with color uniformly. Fit the
valve and tap the coated seat with the valve face in
a rotating manner. To get a clear impression of the
seating contact, use a valve lapper to hold the valve
head.
The ring-like dye impression on the valve face
should be continuous, without any break. The width
of the dye ring, which is the visualized seat width,
should be within the following range:
Cylinder Head Distortion Service Limit: 0.05mm
Tool: Thickness Gauge
Valve Seat Width: 0.9-1.1mm
Tool: Valve Lapper
Lift the valve about 10mm from valve seat. Check
the valve stem deflection in the directions of X and Y
perpendicular to each other, with a dial gauge. If the
deflection measured is out of the limit, replace either
the valve or the valve guide. (If the valve stem is
worn to the limit and the clearance is found to be in
excess of the limit, replace the valve. If the valve
stem is within the limit, replace the valve guide.
Double check the clearance after replacing the
valve stem or the guide).
Valve Stem Deflection (IN & EX): 0.35mm
Tool: Micrometer
Magnetic Stand