Piston-To-Cylinder Clearance; Piston Pin Inspection; Piston Ring Inspection - Yamaha F4 Service Manual

POWR
10 mm (0.4 in)
CRANKCASE, CRANKSHAFT AND CAMSHAFT
a
Oversize piston diameter:
*Over size 1 : 59.25 mm (2.333 in)
Over size 2 : 59.50 mm (2.343 in)
*Except for USA

Piston-to-cylinder clearance

1. Calculate:
9 Piston-to-cylinder clearance
Out of specification ® Replace the
piston and piston rings, the cylinder
or both.
Piston-to-
cylinder
=
clearance
Piston-to-cylinder clearance:
0.035 ~ 0.065 mm
(0.0014 ~ 0.0026 in)

Piston pin inspection

1. Measure:
9 Piston pin outside diameter
Out of specification ® Replace the
piston pin.
Piston pin outside diameter:
12.995 ~ 13.000 mm
(0.5116 ~ 0.5118 in)

Piston ring inspection

1. Measure:
End gap a
9
Out of specification ® Replace the
piston ring.
End gap (installed)
Top ring:
0.10 ~ 0.20 mm
(0.004 ~ 0.008 in)
2nd ring:
0.25 ~ 0.40 mm
(0.010 ~ 0.016 in)
Oil ring:
0.2 ~ 0.7 mm
(0.008 ~ 0.028 in)
NOTE:
Push the piston ring into the cylinder with
the piston crown.
5-31
Cylinder Piston
-
bore diameter
E