Yamaha F400A 2022 - Checking the Piston Ring End Gap; Checking the Piston Ring Groove

7-80
Cylinder block
Checking the piston ring end gap
1. Measure:
• Piston ring end gap “a”
Out of specification → Replace.
TIP:
Level the piston ring “1” in the cylinder using a
piston crown at the specified measuring point
“b”.
Checking the piston ring groove
1. Measure:
• Piston ring groove
Out of specification → Replace.
Piston ring dimensions
Top ring
Height (B)
1.170–1.185 mm (0.0461–
0.0467 in)
Width (T)
2.800–3.000 mm (0.1102–
0.1181 in)
2nd ring
Height (B)
1.170–1.190 mm (0.0461–
0.0469 in)
Width (T)
3.800–4.000 mm (0.1496–
0.1575 in)
Oil ring
Height (B)
2.410–2.470 mm (0.0949–
0.0972 in)
Width (T)
2.350–2.750 mm (0.0925–
0.1083 in)
1
b
a
1
b
a
Piston ring end gap
Measuring point
10.0 mm (0.39 in)
Top ring
End gap
0.20–0.30 mm (0.0079–0.0118
in)
Limit
0.470 mm (0.0185 in)
2nd ring
End gap
0.60–0.75 mm (0.0236–0.0295
in)
Limit
0.900 mm (0.0354 in)
Oil ring
End gap
0.15–0.60 mm (0.0059–0.0236
in)
a. Ring groove (Top)
b. Ring groove (2nd)
c. Ring groove (Oil)
Piston ring groove
Ring groove (Top)
1.22–1.25 mm (0.0480–0.0492
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