Checking The Piston Diameter; Checking The Cylinder Bore; Checking The Piston Ring - Yamaha F150A Service Manual

Bearing separator "2": 90890-06534
Gear puller "3": 90890-06540
General cylindrical tool "4":
a = 19.9 mm (0.78 in)
b = 90.0 mm (3.54 in)
6. Remove the clips "1" and piston pin "2",
and then remove the connecting rod "3".
TIP:
Make sure to keep the parts in the order of
removal.
1
2
3

Checking the piston diameter

1. Measure the piston outside diameter "a"
at the specified measuring point "b".
b
a
Piston diameter "a":
93.921–93.941 mm
(3.6977–3.6985 in)
Measuring point "b":
13.5 mm (0.53 in) above the bottom of
the piston skirt

Checking the cylinder bore

1. Measure the cylinder bore (D
1

Checking the piston ring

1. Measure piston ring dimensions B and T.
7-64
measuring points "a", "b", and "c", and in
directions "d" (D , D
1
D ).
6
a
b D
2
c
D
4
D
6
a. 10.0 mm (0.39 in)
b. 50.0 mm (1.97 in)
c. 85.0 mm (3.35 in)
d. Parallel to the crankshaft
e. At a right angle to the crankshaft
Cylinder bore (D –D
1 6
94.000–94.017 mm
(3.7008–3.7014 in)
a
B
T
c
T
Piston ring dimensions:
Top ring "a":
B: 1.170–1.185 mm (0.0461–0.0467 in)
T: 2.800–3.000 mm (0.1102–0.1181 in)
2nd ring "b":
B: 1.170–1.190 mm (0.0461–0.0469 in)
T: 3.700–3.900 mm (0.1457–0.1535 in)
Oil ring "c":
B: 2.400–2.470 mm (0.0945–0.0972 in)
T: 2.300–2.700 mm (0.0906–0.1063 in)
Crankcase
–D ) at
1 6
, D ) and "e" (D , D
3 5 2
D
1
d
D
e
3
D
5
):
b
B
T
B
,
4