Checking Piston And Piston Ring; Replacing Needle Bearing - Echo PB-251 Service Manual

44

7-7 Checking piston and piston ring

(A)

7-8 Replacing needle bearing

(A)
ENGINE
(B)
(C)
(B)
(D)
(B)
1. Clean piston crown with fine sandpaper or wooden
scraper as required.
2. After removing piston ring, clean piston ring
groove using ring groove cleaning tool.
NOTE: Do not use square end of broken piston ring
when cleaning piston ring groove, otherwise, piston
ring groove might be damaged.
3. Check piston and piston rings for wear or heavy
discoloration. Refer to 1-5 E, G and H. Replace as
required.
4. Remove snap rings from piston and discard them.
5. Push the piston pin out from the piston.
NOTE: If the piston pin is tight, use piston pin tool
897702-30131 (A) with the adapter stamped "8" on
an end and piston holder 897719-02830 (B).
6. Check piston pin and needle bearing for wear or
discoloration. Replace as required.
N O T E : A l w a y s u s e n e e d l e b e a r i n g t o o l
897705-11520 to replace needle bearing on small
end of connecting rod.
1. Put small end on the base (B) of needle bearing
tool and fit needle bearing (A) into the hole of base.
2. Push needle bearing out from small end using
smaller pusher (C).
3. Put small end of connecting rod on the base (B)
aligning both holes of small end and the base.
4. Put new needle bearing on small end.
NOTE: Identification stamped side of needle bear-
ing should face up.
5. Push needle bearing into the bottom using larger
pusher (D).
PB-251