Yamaha F30B 2018, Service Manual

Page: 208 / 348

7-53
Cylinder block
b. Measure the piston ring end gap “b”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
Checking the piston ring groove
1. Measure:
• Piston ring groove
Above specification

Replace.
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-
53) and “Checking the piston ring” (7-52).
Measuring point
10.0 mm (0.39 in)
a. Ring groove (Top)
b. Ring groove (2nd)
c. Ring groove (Oil)
Piston ring groove
Ring groove (Top)
1.21–1.23 mm (0.0476–0.0484
in)
Ring groove (2nd)
1.51–1.53 mm (0.0594–0.0602
in)
Ring groove (Oil)
2.52–2.54 mm (0.0992–0.1000
in)
1
a
b
a
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
0.02–0.06 mm (0.0008–0.0024
in)
Limit
0.110 mm (0.0043 in)
2nd ring
Side clearance
0.02–0.06 mm (0.0008–0.0024
in)
Limit
0.110 mm (0.0043 in)
Oil ring
Side clearance
0.04–0.18 mm (0.0016–0.0071
in)
a
b
c