Yamaha F75F - Checking the Piston Ring; Checking the Piston Ring End Gap

Crankcase
7-49
Checking the piston ring
1. Measure:
• Piston ring dimensions B and T
Below specification  Replace.
Checking the piston ring end gap
1. Measure:
• Piston ring end gap
Above specification  Re
place.
a. Level the piston ring “1” in the cylinder
using a
piston crown at the specified
measuring point “a”.
b. Measure the piston ring end gap “b”.
a. Top ring
b. 2nd ring
c. Oil ring
Piston ring dimensions
Top ring
Height (B)
1.170–1.190 mm (0.0461–0.0469
in)
Width (T)
2.400–2.600 mm (0.0945–0.1024
in)
2nd ring
Height (B)
1.170–1.190 mm (0.0461–0.0469
in)
Width (T)
2.600–2.800 mm (0.1024–0.1102
in)
Oil ring
Height (B)
2.380–2.480 mm (0.0937–0.0976
in)
Width (T)
2.400 mm (0.0945 in)
c
b
a
B
T
T
B
T
B
Top ring
End gap
0.15–0.30 mm (0.0059–0.0118
in)
Limit
0.470 mm (0.0185 in)
2nd ring
End gap
0.70–0.90 mm (0.0276–0.0354
in)
Limit
1.050 mm (0.0413 in)
Oil ring
End gap
0.20–0.70 mm (0.0079–0.0276
in)
Measuring point
10.0 mm (0.39 in)
a
b
1