Motorcycle BMW R1150RT. Manual - part 19
11.11
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 (0.0047)
Piston pin bore dia.
mm (in) 22.005...22.011 (0.8663...0.8666)
Weight classes
+ and —
Weight difference in one class
g (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
Installed direction of piston rings
"Top" marking uppermost
1st groove
asymmetric piston ring,
curved, oval section
Height
mm (in) 1.170...1.190 (0.0461...0.0469)
Wear limit
mm (in) 1.1 (0.0433)
Gap
mm (in) 0.1...0.3 (0.0039...0.0118)
Wear limit
mm (in) 0.8 (0.0315)
Float
mm (in) 0.030...0.070 (0.0012...0.0027)
Wear limit
mm (in) 0.15 (0.0059)
2nd groove
Micro-taper compression ring
Height
mm (in) 1.170...1.190 (0.0461...0.0469)
Wear limit
mm (in) 1.1 (0.0433)
Gap
mm (in) 0.2...0.4 (0.0078...0.0158)
Wear limit
mm (in) 0.8 (0.0315)
Float
mm (in) 0.030...0.07 (0.0012...0.0027)
Wear limit
mm (in) 0.15 (0.0059)
Technical Data 11 Engine
R 1150 RT