Removing And Installing Or Replacing Piston; Replacing Piston Rings - BMW C1 Repair Manual

Removing and installing or
11 25 050
replacing piston
– Remove cylinder.
•
Remove circlip.
11 7 631
•
Remove piston pin with drift, BMW No. 11 7 631.
When installing:
•
Make sure that arrow on piston crown points to-
ward silencer.
e
Caution:
Install a new circlip.
•
Note correct installed position of circlip.
11.62

11 25 671 Replacing piston rings

– Remove cylinder
•
Remove piston rings
C1111020
•
Check piston rings.
•
Measure piston ring gap with piston ring 40 mm
below top edge of cylinder.
Wear values:
Piston ring gap:
Micro-chamfer............................... 0.8 mm (0.03 in)
Taper-face oil-control ring ............. 0.8 mm (0.03 in)
Oil control ring............................... 1.5 mm (0.06 in)
Ring thickness:
Micro-chamfer............................. 0.97 mm (0.04 in)
Taper-face oil-control ring ........... 1.17 mm (0.05 in)
Ring float:
Micro-chamfer............................. 0.1 mm (0.004 in)
Taper-face oil-control ring ........... 0.1 mm (0.004 in)
C1111030
When installing:
•
Install with "Top" uppermost.
•
Turn rings so that gaps are uniformly spaced.
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