CF MOTO CF500-5, Service Manual

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6-25
6 Engine Removal,Inspection & Installation
6 6
6 6
6
Piston
Piston Diameter
Use a micrometer to measure the diameter at the
point 10mm above the piston end, as illustrated on
the right. If the measurement is less that the limit,
replace the piston
Standard: 87.460-87.480mm
Limit: 87.380mm
Tool: Micrometer (75-100mm)
Calculate the piston to cylinder clearance according
to the above measurement.
Piston Ring to Groove Clearance
Use a thickness gauge to measure the side
clearance of top
t
ring and 2
nd
ring.
If the clearance exceeds the limit, replace both
piston and piston rings.
Service Limit:
Top ring: 0.18mm
2
nd
ring: 0.15mm
Standard width of piston ring groove
Top ring: 1.03-1.05mm
2
nd
ring: 1.22-1.24mm
Oil ring: 2.51-2.53mm
If the clearance is more than 0.15mm, replace the
cylinder or piston, or both.
Standard thickness of piston ring
Top ring: 0.970-0.990mm
2
nd
ring: 1.170-1.190mm
Tools: Thickness gauge
Micrometer (0-25mm)