Yamaha MX775 - Page 90

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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