Determining Piston Ring Gaps; Determining Piston Pin Clearance; Assembling Pistons; Removing Ignition Magnet - BMW F 650 GS Repair Manual

Determining piston ring gaps

•
Slip piston ring 60 mm (2.36 in) into cylinder from
top and use a feeler gauge to measure ring gap.
Wear dimension:
Ring gap (all piston rings) .............. 1.0 mm (0.04 in)

Determining piston pin clearance

•
Measure diameter of piston pin bores in piston
stroke direction using an internal micrometer.
•
Measure both ends of piston pin with microme-
ter.
Wear limits:
Bore dia. in piston,
vertical ........................max. 22.030 mm (0.8673 in)
Piston pin dia. ..............min. 21.980 mm (0.8654 in)
Radial clearance in
piston ............................max. 0.050 mm (0.0019 in)

Assembling pistons

11 25 671
L
Note:
The "Top" must face towards the piston crown.
Install the piston rings with their gaps offset
by 120 °.
1
2
3
1 Groove for rectangular-section ring
2 Stepped micro-taper ring
3 Groove for spring-steel oil control ring
•
Use feeler gauge to measure float of piston rings
in groove.
Wear limit,
ring float in groove................... 0.150 mm (0.006 in)

Removing ignition magnet

12 11 070
•
Remove retainer on right engine housing cover.
12 5 500
•
Remove the central plug and install handle,
BMW No. 12 5 500.
•
Remove the cover, noting the thrust
washer (arrow).
E110170
4
•
If necessary, remove ignition trigger (4).
E110180
E110190
E110200
11.35