Yamaha F50F - Checking the Piston Ring Grooves

6C13G11
5-40
1
2
3
4
5
6
7
8
9
2. Level the piston ring
1
in the cylinder
with a piston crown.
3. Check the piston ring end gap
d
at the
specified measuring point. Replace if out
of specification.
Checking the piston ring grooves
1. Measure the piston ring grooves.
Replace the piston if out of specification.
Piston ring dimensions:
Top ring
a
:
B: 1.17–1.19 mm
(0.0461–0.0469 in)
T: 2.30–2.50 mm
(0.0905–0.0984 in)
2nd ring
b
:
B: 1.47–1.49 mm
(0.0579–0.0587 in)
T: 2.60–2.80 mm
(0.1024–0.1102 in)
Oil ring
c
:
B: 2.36–2.48 mm
(0.0929–0.0976 in)
T: (reference data)
2.75 mm (0.1083 in)
Piston ring end gap
d
:
Top ring:
0.15–0.30 mm
(0.0059–0.0118 in)
2nd ring:
0.30–0.50 mm
(0.0118–0.0197 in)
Oil ring:
0.20–0.70 mm
(0.0079–0.0276 in)
Measuring point
e
: 20 mm (0.8 in)
Piston ring groove:
Top ring
a
:
1.21–1.23 mm
(0.0476–0.0484 in)
2nd ring
b
:
1.51–1.53 mm
(0.0594–0.0602 in)
Oil ring
c
:
2.52–2.54 mm
(0.0992–0.1000 in)
Cylinder block