Service manual

5-23
POWR
Power unit
Piston pin and bearing check
1. Check the piston pins and bearings.
Replace if there are signs of heat discol-
oration.
2. Measure the piston pin outside diameter
(using a micrometer 1). Replace if out of
specification.
3. Insert the piston pin into the piston, and
then check the piston-pin-to-piston free
play as shown. Replace the piston pin,
piston, or both if there is free play.
4. Check the piston-pin-to-small-end-bear-
ing-to-connecting-rod free play at the
small end of the connecting rod as
shown. Replace the piston pin, crank-
shaft assy., small end bearing, or all
parts if there is free play or wear at the
small end.
Piston installation
Align each end gap with its respective
locating pin.
1. Install the top ring and 2nd ring.
TIP:
Install the piston rings with the recess for the
locating pin facing up toward the piston
crown.
2. Assemble the bearing 1, washer 2, pis-
ton 3, piston pin 4, and new piston pin
clips 5. NOTICE: Do not reuse a pis-
ton pin clip, always replace it with a
new one.
Piston pin outside diameter:
Standard:
19.995–20.000 mm
(0.7872–0.7874 in)
Limit:
19.990 mm (0.7870 in)
2
1
5
3
4
5
2
a
1
b