Piston Ring Inspection - Yamaha WaveRunner FX140 Service Manual

POWR
CONNECTING RODS AND PISTONS
• If out of specification, replace the piston
and piston rings as a set.
• Measure piston skirt diameter "P" with the
micrometer.
a 5 mm (0.2 in) from the bottom edge of the
piston
Standard
• If out of specification, replace the piston
and piston rings as a set.
• Calculate the piston-to-cylinder clearance
with the following formula.
Piston-to-cylinder clearance =
Cylinder bore "C" –
Piston skirt diameter "P"
Piston-to-cylinder clearance:
0.10–0.11 mm (0.0039–0.0043 in)
<Limit>: 0.17 mm (0.0067 in)
• If out of specification, replace the piston
and piston rings as a set.

Piston ring inspection

1. Measure:
• Piston ring side clearance
Out of specification → Replace the pis-
ton and piston rings as a set.
NOTE:
Before measuring the piston ring side clear-
ance, eliminate any carbon deposits from the
piston ring grooves and piston rings.
Piston ring groove:
Top ring:
0.030–0.065 mm
(0.0012–0.0026 in)
2nd ring:
0.020–0.055 mm
(0.0008–0.0022 in)
5-88
E
Piston size "P"
73.955–73.970 mm
(2.9116–2.9121 in)