Yamaha MX775, Service Manual

Page: 90 / 188

3-50
1
2
3
4
5
6
7
8
9
10
ENGINE
PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT
1.
Measure:
• Piston ring side clearance
Out of specification

Replace the piston and pis-
ton rings as a set.
TIP
Before measuring the piston ring side clearance, eliminate
any carbon deposits from the piston ring grooves and pis-
ton rings.
2.
Install:
• Piston ring
(into the cylinder)
TIP
Use the piston crown to level the piston ring near bottom of
cylinder “a”, where cylinder wear is lowest.
3.
Measure:
• Piston ring end gap
Out of specification

Replace the piston rings as a
set.
Piston ring
Top ring
Side clearance:
0.04–0.08 mm (0.0016–0.0031 in)
Limit:
0.13 mm (0.0051 in)
2nd ring
Side clearance:
0.03–0.07 mm (0.0012–0.0028 in)
Limit:
0.13 mm (0.0051 in)
a
b
b. Upper of cylinder