3-40
PISTON, CONNECTING ROD, CRANKSHAFT AND
CRANKCASE
SCF3730
a
b
3
1
2
3. Remove:
9
Connecting rod cap
9
Connecting rod
Crack/damage/wear
→
Replace the
crankshaft.
4. Measure:
9
Widest portion of the pressed Plasti-
gauge
Out of specification
→
Replace crank-
shaft or connecting rod, and then mea-
sure the clearance again.
PISTON AND PISTON RING INSTALLATION
1. Install:
9
Top ring
1
9
Second ring
2
9
Oil ring
3
NOTE:
9
Be sure to install the top ring and second
ring so that the “R” mark
a
faces toward the
piston head.
9
Make sure that the piston rings move
smoothly.
2. Apply 4-stroke engine oil to the inside of
the connecting rod small end.
3. Install:
9
Piston
1
9
Piston pin
2
9
Piston pin circlip
3
NOTE:
9
Make sure that the “YAMAHA” mark
a
on
the connecting rod faces toward the crank-
case cover.
9
Make sure that the “
∇
” mark
b
on the pis-
ton head faces toward the push rod.
ENG
Connecting rod big end oil clear-
ance:
0.015 ~ 0.040 mm
(0.0006 ~ 0.0016 in)
Wear limit:
0.1 mm (0.004 in)
7CF7E0-03 05.7.3 15:14 Page 40
