Yamaha F100A - Crankshaft Inspection; Main-Bearing Oil Clearance

5-39
POWR
E
CRANKSHAFT AND PISTON/
CONNECTING ROD ASSY.
2. Measure:
● Side clearance a
Out of specification → Replace the
piston and piston rings as a set.
Side clearance:
Top ring:
0.20 ~ 0.80 mm
(0.001 ~ 0.003 in)
2nd ring:
0.03 ~ 0.07 mm
(0.001 ~ 0.003 in)
Oil ring:
0.03 ~ 0.15 mm
(0.001 ~ 0.006 in)
Crankshaft inspection
1. Measure:
● Crankshaft journal diameter
● Crank pin diameter
● Crankshaft runout
Out of specification → Replace the
crankshaft.
Main-bearing oil clearance
1. Measure:
● Main-bearing oil clearance
Out of specification → Replace the
upper and lower bearings as a set.
NOTE:
Measure the main-bearing oil clearance at
room temperature (20 ˚C (68 ˚F)).
Crankshaft journal diameter limit:
47.972 mm (1.8887 in)
Crank pin diameter limit:
43.971 mm (1.7311 in)
Crankshaft runout limit:
0.03 mm (0.001 in)
Main-bearing oil clearance:
0.024 ~ 0.044 mm
(0.0009 ~ 0.0017 in)