Yamaha 60F - Piston Ring; Inspection

5-9
POWR
E
INSPECTION
G62501-0*
PISTON RING
INSPECTION
1. Using a thickness gauge, measure the
clearance between the piston ring and
the groove land.
If the clearance is not within the specifi-
cations, replace the piston.
Å Top/2nd: Keystone type
ı Piston marked with “W” (50, 60, 70 hp)
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. Using a
thickness gauge, measure the end-gap.
If the clearance is not within the specifi-
cations, 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.
Side clearance:
50, 60, 70 hp:
Top/2nd ring:
0.03 ~ 0.07 mm
(0.0012 ~ 0.0028 in)
75, 80, 90 hp:
Top/2nd ring:
0.03 ~ 0.06 mm
(0.0012 ~ 0.0024 in)
Ring end gap (installed):
50, 60, 70 hp:
0.3 ~ 0.5 mm (0.012 ~ 0.020 in)
75, 80, 90 hp:
0.4 ~ 0.6 mm (0.016 ~ 0.024 in)
Åı