BMW R 1150 GS Repair Manual page 57

Technical Data
Pistons
Piston dia.
A
Wear limit
B
Wear limit
AB
Wear limit
Installed clearance
Total wear clearance of piston and cylinder
Piston pin bore
Weight classes
Weight difference in one class
Direction of installation
Piston rings
1st groove Piston ring
asymmetric, convex oval
Height
Wear limit
Ring gap
Wear limit
Ring float
Wear limit
2nd groove Micro-taper compression ring
Height
Wear limit
Ring gap
Wear limit
Ring float
Wear limit
3rd groove Coiled-spring
Height
Wear limit
Ring gap
Wear limit
Ring float
Wear limit
Installed direction of piston rings
11.10
mm (in) 100.971 ... 100.983 (3.9753 ... 3.9758)
mm (in) 100.895 (3.9723)
mm (in) 100.983 ... 100.995 (3.9757 ... 3.9763)
mm (in) 100.905 (3.9727)
mm (in) 100.979 ... 100.987 (3.9756 ... 3.9759)
mm (in) 100.900 (3.9725)
mm (in) 0.005 ... 0.029 (0.0002 ... 0.0011)
mm (in) 0.12 (0.005)
mm (in) 22.005 ... 22.011 (0.8664 ... 0.8666)
grammes (oz.) 10 (0.353) (complete with pins and rings)
mm (in) 1.170 ... 1.190 (0.0461 ... 0.0469)
mm (in) 1.1 (0.04)
mm (in) 0.1 ... 0.3 (0.004 ... 0.012)
mm (in) 0.8 (0.03)
mm (in) 0.030 ... 0.070 (0.0012 ... 0.0027)
mm (in) 0.15 (0.006)
mm (in) 1.170 ... 1.190 (0.0461 ... 0.0469)
mm (in) 1.1 (0.04)
mm (in) 0.2 ... 0.4 (0.0078 ... 0.0158)
mm (in) 0.8 (0.03)
mm (in) 0.030 ... 0.07 (0.0012 ... 0.0027)
mm (in) 0.15 (0.0006)
ring
mm (in) 1.97 ... 1.99 (0.0776 ... 0.0783)
mm (in) 1.9 (0.075)
mm (in) 0.30 ... 0.55 (0.012 ... 0.02166)
mm (in) 1.20 (0.047)
mm (in) 0.020 ... 0.060 (0.0008 ... 0.0024)
mm (in) 0.15 (0.006)
R 1150 GS
(Measuring plane A — see Checking pistons
and cylinders)
+ and —
Arrow on piston crown pointing to exhaust side
Production locating point towards exhaust
side (see Installing piston)
Top marking uppermost