Installing Flywheel; Checking Piston And Piston Ring - Bosch PB-650 Service Manual

PB-650
PB-750

8-8 Installing flywheel

8-9 Checking piston and piston ring

A
B
C
1K359
ENGINE
(B)
(A)
Cut view A
Cut view B
Cut view C
(A)
1. Install flywheel matching key way (A) of flywheel
to key (B) on crankshaft. Tighten nut by hand.
NOTE: If starter is installed, pull starter rope out
about 20 cm (8 in) and make a temporary knot at
the end of rope guide before inserting piston stop-
per in spark plug hole. After inserting piston stopper,
pull out starter handle and untie temporary knot.
Rotate flywheel counterclockwise until it stops at pis-
ton stopper. Then release rope.
2. Insert piston stopper 897537-30130 in the spark
plug hole by hand.
3. Install the nut to flywheel and tighten it.
4. Reinstall all the parts, which have been removed,
1. Clean the piston crown with a fine sandpaper or
wooden scraper as required.
2. After removing piston rings, clean the ring groove
using a ring groove cleaning tool.
NOTE : Do not use the squared end of broken pis-
ton ring when cleaning the 1st piston ring groove of
PB-650 and PB-750, because the 1st piston ring is
key-stone ring and the 1st ring groove is trapezoid
shape to meet the key-stone ring.
If clean the 1st ring groove using the end of broken
piston ring, 1st ring groove might be scratched.
3. Check the piston and piston rings for wear or
heavy discoloration. Replace as required.
4. Remove piston pin circlips from the piston and
discard them.
5. Push the piston pin out from the piston.
NOTE: If the piston pin is tight, use the piston pin
tool 897702-30131 (A) with the adapter stamped
"10" on an end and piston holder 897719-02830 (B).
6. Check the piston pin and needle bearing for wear
or discoloration. Replace as required.
(B)
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