3-40
ENG
PISTON, CONNECTING ROD, CRANKSHAFT AND
CRANKCASE
PISTON RING INSPECTION
1. Measure:
• Piston ring end gap
Out of specification
→
Replace.
NOTE:
Insert the piston ring
1
into the cylinder, and
push it approximately 5 mm (0.2 in) into the cylin-
der. Push in the ring with the piston crown so that
the ring is at right angles to the cylinder bore.
Ring end gap
Wear limit
Top ring
0.20 ~ 0.40 mm
(0.0079 ~ 0.0157 in)
0.65 mm
(0.0256 in)
2nd ring
0.20 ~ 0.40 mm
(0.0079 ~ 0.0157 in)
0.75 mm
(0.0295 in)
Oil ring
0.20 ~ 0.70 mm
(0.0079 ~ 0.0276 in)
0.9 mm
(0.0354 in)
SVU3630J
2. Measure:
• Piston ring side clearance
Out of specification
→
Replace.
Use a thickness gauge
1
.
NOTE:
• Clean carbon deposits from the piston ring
grooves and rings before measuring the
side clearance.
• Measure the side clearance at several portions.
Piston ring side
clearance
Wear limit
Top ring
0.04 ~ 0.08 mm
(0.0016 ~
0.0031 in)
0.13 mm
(0.0051 in)
2nd ring
0.02 ~ 0.06 mm
(0.0008 ~
0.0024 in)
0.12 mm
(0.0047 in)
SVU3640J
