Yamaha F40B - Checking the Piston Ring Side Clearance; Checking the Piston Pin Boss Bore; Checking the Piston Pin Diameter; Checking the Connecting Rod Small End Inside Diameter and Big End Inside Diameter

POWR
Power unit
5-45 67C3K11
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.
Checking the piston pin boss bore
1. Measure the piston pin boss bore.
Replace the piston if out of specification.
Checking the piston pin diameter
1. Measure the piston pin diameter.
Replace if out of specification.
Checking the connecting rod small
end inside diameter and big end
inside diameter
1. Tighten the connecting rod cap bolts to
the specified torques in 2 stages.
2. Measure the connecting rod small end
inside diameter a and big end inside
diameter b. Replace the connecting rod
if out of specification.
Piston ring side clearance:
Top ring a:
0.02–0.06 mm
(0.0008–0.0024 in)
2nd ring b:
0.02–0.06 mm
(0.0008–0.0024 in)
Oil ring c:
0.04–0.18 mm
(0.0016–0.0071 in)
Piston pin boss bore:
15.974–15.985 mm
(0.6289–0.6293 in)
S67C5131
a
b
c
S6AU5137
Piston pin diameter:
15.965–15.970 mm
(0.6285–0.6287 in)
T
R
.
.
Connecting rod cap bolt:
1st: 6 N·m (0.6 kgf·m, 4.4 ft·lb)
2nd: 17 N·m (1.7 kgf·m, 12.5 ft·lb)
Connecting rod small end inside
diameter a:
15.985–15.998 mm
(0.6293–0.6298 in)
Connecting rod big end inside
diameter b:
36.000–36.024 mm
(1.4173–1.4183 in)
S67C5134
b
a