Piston Ring Inspection - Yamaha EF3000iSE Service Manual

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.
SVU3630J
Top ring
2nd ring
Oil ring
2. Measure:
• Piston ring side clearance
Out of specification → Replace.
Use a thickness gauge 1.
Top ring
SVU3640J
2nd ring
NOTE:
• Clean carbon deposits from the piston ring
grooves and rings before measuring the
side clearance.
• Measure the side clearance at several portions.
3-40
ENG
Ring end gap Wear limit
0.20 ~ 0.40 mm
(0.0079 ~ 0.0157 in) (0.0256 in)
0.20 ~ 0.40 mm
(0.0079 ~ 0.0157 in) (0.0295 in)
0.20 ~ 0.70 mm
(0.0079 ~ 0.0276 in) (0.0354 in)
Piston ring side
Wear limit
clearance
0.04 ~ 0.08 mm
(0.0016 ~
(0.0051 in)
0.0031 in)
0.02 ~ 0.06 mm
(0.0008 ~
(0.0047 in)
0.0024 in)
0.65 mm
0.75 mm
0.9 mm
0.13 mm
0.12 mm