Checking The Piston Ring Groove; Checking The Piston Ring Side Clearance; Checking The Connecting Rod Big End Side Clearance; Checking The Crankshaft - Yamaha F150B Service Manual

POWR
Piston ring end gap a:
Top ring:
0.15–0.30 mm (0.0059–0.0118 in)
Second ring:
0.30–0.45 mm (0.0118–0.0177 in)
Oil ring:
0.15–0.60 mm (0.0059–0.0236 in)
Measuring point b:
20 mm (0.8 in)

Checking the piston ring groove

1. Measure the
Replace the piston and connecting rod
assembly if out of specification.
Piston ring groove:
Top ring a:
1.23–1.25 mm (0.0484–0.0492 in)
Second ring b:
1.22–1.24 mm (0.0480–0.0488 in)
Oil ring c:
2.51–2.53 mm (0.0988–0.0996 in)
Checking the piston ring side
clearance
1. Measure the piston ring side clearance.
Replace the piston and connecting rod
assembly, piston ring set if out of specifi-
cation.
7-55
Power unit
piston ring grooves.
a
b
c
a
b
c
Piston ring side clearance:
Top ring a:
0.04–0.08 mm (0.0016–0.0031 in)
Second ring b:
0.03–0.07 mm (0.0012–0.0028 in)
Oil ring c:
0.04–0.13 mm (0.0016–0.0051 in)
Checking the connecting rod big end
side clearance
1. Measure the connecting rod big end side
clearance a.
Connecting rod big end
side clearance a (reference data):
0.14–0.31 mm (0.006–0.012 in)

Checking the crankshaft

1. Measure the crankshaft journal diameter
a, crankpin diameter b, and crankpin
width c. Replace the crankshaft if out of
specification.
a
a