Piston Ring - Yamaha 25J Manuel D'entretien

POWR
Å
INSPECTION
G62501-0

PISTON RING

Inspection
1. Using a feeler gauge, measure the
clearance between the piston ring and
the ring groove.
Side clearance:
Top ring and 2nd ring:
0.05 ~ 0.09 mm
(0.002 ~ 0.004 in)
If the clearance is not within the specifi-
cations, replace the piston.
Å Top/2nd: Keystone type
2. Insert the piston ring into the cylinder.
Using a piston, push the piston ring a
little beyond the bottom of the ring
travel to a depth of 20 mm (0.8 in) from
the top of the cylinder block.
CAUTION:
Take care not to scratch the piston.
NOTE:
Using a thickness gauge, measure the end-
gap.
Ring end gap (installed):
Top ring and 2nd ring:
0.15 ~ 0.30 mm
(0.006 ~ 0.012 in)
If the clearance is greater than the maxi-
mum, replace the piston-ring.
NOTE:
If the clearance is greater than maximum
even with a new piston ring, rebore the cyl-
inder and use an over-size piston and pis-
ton ring.
5-7
E