Yamaha F50A - Checking the Piston Ring Grooves; Checking the Piston Ring Side Clearance; Checking the Piston Pin Boss Bore; Checking the Piston Pin

62Y3A11
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Checking the piston ring grooves
1. Measure the piston ring grooves.
Replace the piston if out of specification.
Checking the piston ring side
clearance
1. Measure the piston ring side clearance.
Replace the piston and piston rings as a
set if out of specification.
Checking the piston pin boss bore
1. Measure the piston pin boss bore.
Replace the piston if out of specification.
Checking the piston pin
1. Measure the piston pin diameter.
Replace if out of specification.
Piston ring groove:
Top ring
a
:
1.23–1.25 mm (0.048–0.049 in)
Second ring
b
:
1.52–1.54 mm (0.060–0.061 in)
Oil ring
c
:
2.51–2.53 mm (0.099–0.100 in)
Piston ring side clearance:
Top ring
a
:
0.04–0.08 mm (0.002–0.003 in)
Second ring
b
:
0.03–0.07 mm (0.001–0.003 in)
Oil ring
c
:
0.05–0.19 mm (0.002–0.007 in)
Piston pin boss bore:
15.974–15.985 mm (0.6289–0.6293 in)
Piston pin diameter:
15.965–15.970 mm (0.6285–0.6287 in)
Cylinder body