PB-251
ENGINE
46
7-11 Assembling crankshaft and crankcase
1. Clean mating surface of each crankcase half.
2. Insert crankshaft starter end into starter side of
crankcase half until properly seated. If hard to in-
sert, preheat ball bearing using floodlight or suitable
heater for easier installation.
3. Place new crankcase gasket (A) on starter side
crankcase half.
4. Reassemble both crankcase halves together en-
suring that dowel pins on crankcase half are properly
seated in holes of the opposite crankcase half.
5. Tighten three bolts to secure crankcase halves
together and check crankshaft rotation.
NOTE:
The torque differences among three bolts
should not exceed 20kgf•cm (17in•lbf).
6. Carefully remove excess portion of crankcase
gasket (B) with sharp knife.
7-12 Installing piston
1. Lubricate needle bearing (A) with two-stroke oil.
2. Insert needle bearing (A) into small end of con-
necting rod.
3. Place piston over small end of connecting rod so
that arrow mark (B) on piston points toward exhaust
side.
4. Insert piston pin guide (C) stamped “8” through
piston, washers (D) and needle bearing in connect-
ing rod.
5. Insert piston pin (E) in piston pushing out piston
pin guide (C) using piston pin tool 897702-30131
(F).
NOTE:
Piston holder 897719-02830 (G) is recom-
mended for easier installation.
6. Install new snap rings to piston pin bore, and be
sure that they are properly seated in the grooves.
(A)
(B)
(C)
(D)
(G)
(E)
(F)
(A)
Summary of Contents for PB-251
Page 1: ...Ord No 403 16...
