BMW R 1100 S, Repair Manual

Page: 57 / 311

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