Checking The Piston Ring Grooves; Checking The Piston Ring Side Clearance; Checking The Connecting Rod Big End Side Clearance - Yamaha F150A Service Manual

POWR
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.
Piston ring end gap d:
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 e: 20 mm (0.8 in)

Checking the piston ring grooves

1. Measure the
Replace the piston if out of specification.
5-43
Power unit
piston ring grooves.
a
b
c
S63P5720
Piston ring groove:
Top ring a:
1.23–1.25 mm (0.048–0.049 in)
Second ring b:
1.22–1.24 mm (0.048–0.049 in)
Oil ring c:
2.51–2.53 mm (0.099–0.100 in)
Checking the piston ring side
clearance
1. Measure the piston ring side clearance.
Replace the piston and piston rings as a
set if out of specification.
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. Replace the connecting
rod or crankshaft, or both if out of specifi-
cation.
a
b
c
S63P5730
63P3F11