Yamaha F75F - Checking the Piston Pin Boss Inside Diameter; Checking the Piston Ring Groove; Checking the Piston Ring Side Clearance

Crankcase
7-50
Checking the piston ring groove
1. Measure:
• Piston ring groove
Above specification  Re
place.
Checking the piston ring side clear-
ance
1. Measure:
• Piston ring side clearance
Above specification  Check the
piston
ring grooves and piston ring.
See “Checking the piston ring groove”
(7-50) and “Checking the piston ring”
(7-49).
Checking the piston pin boss inside
diameter
1. Measure:
• Piston pin boss inside diameter “a”
Above specification  Replace.
a. Ring groove (Top)
b. Ring groove (2nd)
c. Ring groove (Oil)
Piston ring groove
Ring groove (Top)
1.23–1.25 mm (0.0484–0.0492
in)
Ring groove (2nd)
1.22–1.24 mm (0.0480–0.0488
in)
Ring groove (Oil)
2.51–2.53 mm (0.0988–0.0996
in)
a
b
c
a. Top ring side clearance
b. 2nd ring side clearance
c. Oil ring side clearance
Piston ring side clearance
Top ring
Side clearance
0.04–0.08 mm (0.0016–0.0032
in)
Limit
0.130 mm (0.0051 in)
2nd ring
Side clearance
0.03–0.07 mm (0.0012–0.0028
in)
Limit
0.110 mm (0.0043 in)
Oil ring
Side clearance
0.03–0.15 mm (0.0012–0.0059
in)
a
b
c