Yamaha Scorpio, Service Manual

Page: 110 / 300

4 - 33
ENG
CYLINDER AND PISTON
YP402111
PISTON RINGS INSPECTION
1.Measure:
●
Side clearance
Out of specification
→
Replace the piston
and the piston rings as a set.
NOTE:
Eliminate the carbon deposits from the piston
ring grooves and piston rings before measur-
ing the side clearance.
Side clearance (piston ring):
Top ring:
0.03 ~ 0.07 mm
<Limit 0.1 mm>
2 nd ring:
0.02 ~ 0.06 mm
<Limit: 0.1 mm>
2.Position:
●
Piston rings
(into the cylinder)
NOTE:
Push the ring with the piston crown so that the
ring will be at a right angle to the cylinder bore.
3.Measure:
End gap
Out of specification
→
Replace.
NOTE:
You cannot measure the end gap on the
expander spacer of the oil ring. If the oil ring
rails show excessive gap, replace all three
rings.
a
40.0 mm
End gap:
Top ring
0.15 ~ 0.30 mm
<Limit: 0.6 mm>
2 nd ring:
0.15 ~ 0.30 mm
<Limit: 0.6 mm>
Oil ring:
0.3 ~ 0.9 mm