Yamaha 20C Manual De Servicio página 152

POWR
INSPECTION
G61501-0*
PISTON RING
Inspection
1) Using a feeler gauge, measure the clearance
between the piston ring and the groove land.
Side clearance:
Top ring:
0.02 – 0.06 mm (0.0008 – 0.0024 in)
2nd:
0.03 – 0.07 mm (0.0012 – 0.0028 in)
If the clearance is not within the specifications,
replace the piston.
å Top
∫ 2nd
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.
cC
Take care not to scratch the piston. Using a
thickness gauge, measure the end-gap.
Ring end gap:
0.30 – 0.35 mm (0.0118 – 0.0197 in)
If the clearance is greater than the maximum,
replace the piston-ring and/or piston.
NOTE:
If the clearance is greater than maximum even with
a new piston ring, rebore the cylinder and use an
over-size piston and piston-ring.
5-19
E