BMW Motorcycle (R1100RT, R1100RS, R850/1100GS, R850/1100R). Manual - part 11

11.36

Piston pin bore dia.

mm (in) 22.005...22.011 

(0.86634...0.866575)

22.005...22.011 
(0.86634...0.866575)

Weight classes

+ and —

+ and —

Weight difference in one class

g (oz.) 10 (0.35)

(complete with pins and 
rings)

10 (0.35)
(complete with pins and 
rings)

Direction of installation

Arrow on piston crown 
pointing to exhaust side

Arrow on piston crown 
pointing to exhaust side

Production location 
towards exhaust side 
(see Installing Piston)

Production location 
towards exhaust side 

a

(see Installing Piston)

Piston rings

1st groove

Micro-taper compression ring

B-Ring SPT TOP

Height

mm (in)

1.170...1.190
(0.04606...0.04685)

1.175...1.190 
(0.04626...0.04685)

Wear limit

mm (in) 1.1 (0.043307)

1.1 (0.043307)

Gap clearance

mm (in)

0.1...0.3 
(0.003937...0.0118)

0.1...0.3 
(0.003937...0.0118)

Wear limit

mm (in) 0.8 (0.031496)

0.8 (0.031496)

Side clearance

mm (in)

0.030...0.070
(0.00118...0.0027559)

0.040...0.075 
(0.001575...0.002953)

Wear limit

mm (in) 0.15 (0.00591)

0.15 (0.00591)

2nd groove Micro-taper compression ring

M-Ring m Ø TOP 4 DZ

Height

mm (in)

1.170...1.190
(0.04606...0.04685)

1.175...1.190 
(0.04626...0.04685)

Wear limit

mm (in) 1.1 (0.043307)

1.1 (0.043307)

Gap clearance

mm (in)

0.3...0.5 
(0.0118...0.019685)

0.1...0.3 
(0.003937...0.0118)

Wear limit

mm (in) 1.00 (0.03937)

0.8 (0.031496)

Side clearance

mm (in)

0.030...0.070
(0.00118...0.0027559)

0.030...0.065 
(0.00118...0.002559)

Wear limit

mm (in) 0.15 (0.00591)

0.15 (0.00591)

3rd groove Equal-chamfer ring + tubular spring

Height

mm (in)

2.475...2.490 
(0.09744...0.09803)

2.475...2.490 
(0.09744...0.09803)

Wear limit

mm (in) 2.4 (0.094488)

2.4 (0.094488)

Gap clearance

mm (in)

0.30...0.60 
(0.011811...0.023622)

0.30...0.60 
(0.011811...0.023622)

Wear limit

mm (in) 1.20 (0.047244)

1.20 (0.047244)

Side clearance

mm (in)

0.020...0.060 
(0.000787...0.0023622)

0.020...0.055 
(0.000787...0.002165)

Wear limit

mm (in) 0.15 (0.00591)

0.15 (0.00591)

Installed direction of piston rings

"Top" marking uppermost "Top" marking uppermost

Piston pin

Piston pin dia.

mm (in)

21.995...22.000 
(0.86594...0.86614)

21.995...22.000 
(0.86594...0.86614)

Wear limit

mm (in) 21.960 (0.864567)

21.960 (0.864567)

Bore dia. in piston

mm (in)

22.005...22.011 
(0.866339...0.8665748)

22.005...22.011 
(0.866339...0.8665748)

Radial clearance in piston

mm (in)

0.005...0.016 
(0.000197...0.0006299)

0.005...0.016 
(0.000197...0.0006299)

Wear limit

mm (in) 0.070 (0.0027559)

0.070 (0.0027559)

Technical Data

R 850 R

R 1100 R

11.37

Sectioned drawing of engine

RS119010

11.38

Lubricating oil circuit

RS119020

11.39

Coolant circuit

RS119030

11.40

Cooling oil circuit (with oil thermostat)

RT119010

11.41

Removing engine

L

 Note:

Auxiliary shaft, timing chains, chain tensioner/guide 
rails and crankshaft can only be dismantled after the 
engine has been removed. All other components 
can be dismantled while the engine is still installed.

•

Drain engine oil.

•

[RT] Remove lower section of fairing.

•

Attach stand, BMW  No. 00 1 520 to motorcycle.

•

[GS] Use extension bushings and bolts, 
BMW No. 00 1 527.

GS

00 1 520

RS110520

11.42

•

Remove dualseat.

•

[RS/GS/RT] Remove side sections of fairing.

•

[RS] Detach inner cockpit panel (1) at fuel tank.

•

[R] Unscrew fuel tank cover.

•

[RT] Detach storage compartment from tank.

•

Unfasten fuel tank mount (2).

•

Seal, loosen and pull off fuel feed and return line 
(3) with hose clip, BMW No. 13 3 010.

•

Remove vent pipes (4).

•

Remove connector at fuel pump (5).

•

Remove fuel tank.

2

5

1

3

4

13 3 010

RS

RS160010

11.43

C

A

B

C

A

B

6x

6x

RT

13 3 010

3

5

4

RT160060