Yamaha F100A - Piston Ring Inspection; Piston-To-Cylinder Clearance

5-38
POWR
E
CRANKSHAFT AND PISTON/
CONNECTING ROD ASSY.
Piston-to-cylinder clearance
1. Calculate:
● Piston-to-cylinder clearance
Out of specification → Replace the
piston and piston rings, the cylinder
block or both.
Piston-to-
cylinder
clearance
=
Cylinder
bore
–
Piston
diameter
Piston-to-cylinder clearance:
0.070 ~ 0.080 mm
(0.0028 ~ 0.0031 in)
Piston ring inspection
1. Measure:
● End gap a
Out of specification → Replace the
piston rings as a set.
NOTE:
Push the piston ring into the cylinder with
the piston crown.
End gap (installed):
Top ring:
0.15 ~ 0.30 mm
(0.006 ~ 0.012 in)
2nd ring:
0.70 ~ 0.90 mm
(0.028 ~ 0.035 in)
Oil ring:
0.20 ~ 0.70 mm
(0.008 ~ 0.028 in)