Yamaha F115A - Checking the Crankshaft; Checking the Main-Bearing Oil Clearance

5-40
POWR
E
CRANKSHAFT AND PISTON/
CONNECTING ROD ASSEMBLY
2. Measure:
• Side clearance a
Out of specification → Replace the pis-
ton and piston rings as a set.
Side clearance
Top ring
0.02 - 0.08 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)
5490
CHECKING THE CRANKSHAFT 5
Measure:
• Crankshaft journal diameter
• Crank pin diameter
• Crankshaft runout
Out of specification → Replace the
crankshaft.
CHECKING THE MAIN-BEARING OIL
CLEARANCE
5
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)
Crankshaft runout limit
0.03 mm (0.001 in)
Main-bearing oil clearance
0.024 - 0.044 mm
(0.0009 - 0.0017 in)
5500