Piston Ring Inspection - Yamaha EF1000iS Service Manual

CRANKSHAFT, PISTON AND PISTON RING
a
4. Measure:
9 Piston pin diameter a
Out of specifications → Replace.
Piston pin diameter:
a
5. Inspect:
9 Check the piston pin enters smoothly
into the piston pin hole.
If the piston pin fits tightly into the pis-
ton, check the piston pin hole. If there is
any protrusion, use a knife or scraper to
gently remove it so that piston pin can
be pushed in gently with your fingers.

PISTON RING INSPECTION

1. Measure:
1
9 Piston ring end gap
Out of specification → Replace.
NOTE:
Insert the piston ring 1 into the cylinder, and
push it approximately a 5 mm (0.2 in) into the
cylinder. Push the ring with the piston crown
so that the ring is at angles to the cylinder
bore.
Top ring
2nd ring
Oil ring
Out of specifications → Replace the
piston and piston ring as a set.
3-24
ENG
9.99 ~ 10.00 mm
(0.3933 ~ 0.3937 in)
Limit:
9.95 mm
(0.3917 in)
Ring end gap
0.10 ~ 0.30 mm
(0.0039 ~ 0.0118 in)
0.10 ~ 0.30 mm
(0.0039 ~ 0.0118 in)
0.2 ~ 0.7 mm
(0.0078 ~ 00275 in)
Wear limit
0.6 mm
(0.0236 in)
0.6 mm
(0.0236 in)
0.9 mm
(0.0354 in)