Removing Piston; Disassembling Piston; Determining Clearance Of Piston In Cylinder - BMW F 650 GS Repair Manual

Removing piston

11 25 050
•
Remove piston pin circlips.
•
Press out piston pin with drift,
BMW No. 11 6 581.
L
Note:
Mark exhaust-valve side on piston crown.

Disassembling piston

11 25 671
•
Remove piston rings with piston ring pliers.
•
Carefully clean piston.
•
Check piston for signs of damage.
11.34
Determining clearance of piston in
cylinder
1
2
•
Measure cylinder bore at 55...65 mm
(2.17...2.56 in) from the upper edge with an inter-
nal micrometer at three points (1, 2, 3).
•
Make a note of the largest value as
dimension "A".
B
•
Measure piston diameter "B" at distance
H=16 mm (0.63 in) from the lower edge at a right
angle to the piston pin axis.
L
Note:
Determine piston clearance:
Dimension "A" minus dimension "B" = piston clear-
ance
Piston clearance:
When new ... 0.024...0.040 mm (0.0009...0.0016 in)
Wear limit ...................... max. 0.100 mm (0.0039 in)
3
E110150
H
E110160