3. Inspect breather return pipe. If cracked/leaked/damaged, replace.
Piston
Measure piston outside diameter at the specified measuring point. If out of specification, replace.
Piston diameter: 58.950～58.965mm
Measuring point○
a
: 10mm
Cylinder bore
1. Measure cylinder bore separately at measuring point ○1, ○2, ○3 . At each point, measure the
cylinder bore at places D1, D3, D5 parallel to the crankcase and at places D2, D4, D6 vertical to
the crankshaft.
a
D
②
③
①
D1&D2
D3&D4
D5&D6
Measuring point height:
○
1
100mm；
○
2
40mm；
○
3
70mm
Cylinder bore: 59～59.02mm
Limit size: 59.10mm
2. Calculate taper limit and round limit. If out of specification, replace crankcase.
Taper limit: 0.08mm(D1-D5, D2-D6)
Round limit: 0.05mm(D2-D1, D6-D5)
Piston pin diameter
Measure piston pin outside diameter. If out of specification, replace the piston pin.
Piston pin outside diameter: 12.995～13.000mm
Piston ring
1. Push the piston ring parallel with the piston crown into the specified measuring point of the
cylinder (10mm from conjunction surface).
2. Measure end gap by space gauge. If out of specification, replace the piston ring.
End gap (installed) / limit size: Top ring 0.10～0.20mnm/0.4mm
2nd ring 0.25～0.40mm/0.6mm
Oil ring 0.2～0.7mm/0.9mm
3. Install piston ring to piston, and measure side clearance between piston ring and its slot by
clearance gauge. If out of specification, replace the piston ring.
Side clearance: Top ring 0.04～0.08mnm
2nd ring 0.02～0.06mm
Camshaft decompressor
1. Inspect camshaft decompressor, gear, and weight. If gear is worn/damaged/cracked, replace.
54
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