BMW Motorcycle (R1100RT, R1100RS, R850/1100GS, R850/1100R). Manual - part 9

11.20

Piston pin bore dia.

mm (in)

22.005...22.011 
(0.86634...0.866575)

Weight classes

+ and —

Weight difference in one class

g (oz.)

10 (0.35) (complete with 
pins and rings)

Direction of installation

Arrow on piston crown 
pointing to exhaust side

Production locating 
towards exhaust side 

a

 (see Installing piston)

Piston rings

1st groove

Micro-taper compression ring

Height

mm (in)

1.175...1.190 
(0.04626...0.04685)

Wear limit

mm (in)

1.1 (0.043307)

Gap clearance

mm (in)

0.1...0.3 
(0.003937...0.0118)

Wear limit

mm (in)

0.8 (0.031496)

Side clearance

mm (in)

0.040...0.075 
(0.001575...0.002953)

Wear limit

mm (in)

0.15 (0.00591)

2nd groove Micro-taper compression ring

Height

mm (in)

1.175...1.190 
(0.04626...0.04685)

Wear limit

mm (in)

1.1 (0.043307)

Gap clearance

mm (in)

0.1...0.3 
(0.003937...0.0118)

Wear limit

mm (in)

0.8 (0.031496)

Side clearance

mm (in)

0.030...0.065 
(0.00118...0.002559)

Wear limit

mm (in)

0.15 (0.00591)

3rd groove  Equal-chamfer ring + tubular spring

Height

mm (in)

2.475...2.490 
(0.09744...0.09803)

Wear limit

mm (in)

2.4 (0.094488)

Gap clearance

mm (in)

0.30...0.60 
(0.011811...0.023622)

Wear limit

mm (in)

1.20 (0.047244)

Side clearance

mm (in)

0.020...0.055 
(0.000787...0.002165)

Wear limit

mm (in)

0.15 (0.00591)

Installed direction of piston rings

"Top" marking 
uppermost

Piston pin

Piston pin dia.

mm (in)

21.995...22.000 
(0.86594...0.86614)

Wear limit

mm (in)

21.960 (0.864567)

Bore dia. in piston

mm (in)

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

Radial clearance in piston

mm (in)

0.005...0.016 
(0.000197...0.0006299)

Wear limit

mm (in)

0.070 (0.0027559)

Technical Data

R 1100 RT

11.21

Technical Data

R 850 GS

R 1100 GS

Engine, general

Engine design

Four-stroke flat twin, air-cooled with oil-cooled 
exhaust ports, installed longitudinally, 4 valves 
per cylinder, two high-mounted camshafts, elec-
tronic fuel injection.

Location of engine number

Crankcase

Cylinder bore

mm (in) 87.5 (3.445)

99.0 (3.898)

Stroke

mm (in) 70.5 (2.776)

70.5 (2.776)

Effective displacement

cc 848

1085

Compression ratio

10.3 : 1

10.3 : 1

Power output 

kW(bhp)/min

-1

52(70)/7000

59(80)/6750

Max. torque 

Nm/min

-1

77/5500

97/5250

Permissible maximum engine speed

min

-1

8100

7800

Permissible continuous engine speed

min

-1

7800

7600

Idle speed

min

-1

1000 

+150

1000 

+150

Direction of rotation

Clockwise, looking at 
ignition system

Clockwise, looking at 
ignition system

Compression test pressure

good
normal

poor

bar (psi)
bar (psi)

bar (psi)

above 10 (145.04)
8.5...10 
(123.28...145.04)
below  8.5(123.28)

above 10 (145.04)
8.5...10 
(123.28...145.04)
below  8.5(123.28)

Intake port dia./cylinder head

mm (in) 44 (1.732)

44 (1.732)

Lubrication system

Theoretical vol. in circulation at 6000 min

-1

Lubricating oil 

l (Imp. pints)

Cooling oil 

l (Imp. pints)

36 (63.36)
30 (52.8)

36 (63.36)
30 (52.8)

Oil filter

Full-flow type

Full-flow type

Pressure differential needed to open 
bypass valve

bar (psi) 1.5 (21.756)

1.5 (21.756)

Oil pressure warning light comes on below

bar (psi) 0.2...0.5 (2.9...7.25)

0.2...0.5 (2.9...7.25)

Pressure relief valve opens at

bar (psi) 5.5 (79.77)

5.5 (79.77)

Operating pressure

bar (psi) 3.5...6.0 (50.76...87.02) 3.5...6.0 (50.76...87.02)

Oil content

without filter change 

l (Imp. pints)

with filter change 

l (Imp. pints)

min/max l 

(Imp. 

pints)

3.50 (6.16)
3.75 (6.6)
0.50 (0.88)

3.50 (6.16)
3.75 (6.6)
0.50 (0.88)

Permissible oil consumption

l/1000 km

Imp.pint/miles

1.0
(1.41/500)

1.0
(1.41/500)

Oil pumpe

Oil pump

2 Duocentric pumps

2 Duocentric pumps

Housing depth

mm (in)
mm (in)

12.02...12.05 
(0.47322...0.47441)
10.02...10.05 
(0.3945...0.3957)

12.02...12.05 
(0.47322...0.47441)
10.02...10.05 
(0.3945...0.3957)

Height of rotor

mm (in)
mm (in)

11.95...11.98 
(0.4705...0.4717)
9.95...9.98 
(0.3917...0.3929)

11.95...11.98 
(0.4705...0.4717)
9.95...9.98 
(0.3917...0.3929)

Axial play

mm (in) 0.04...0.1 

(0.0016...0.0039)

0.04...0.1 
(0.0016...0.0039)

Wear limit

mm (in) 0.25 (0.0098)

0.25 (0.0098)

11.22

Valves

Included angle between valves

° 41

41

Valve clearance with engine cold (max. 35 °C)

Inlet valve

mm (in) 0.15 (0.0059)

0.15 (0.0059)

Exhaust valve

mm (in) 0.30 (0.0118)

0.30 (0.0118)

Valve timing

At zero valve clearance and 3 mm (0.1181 in) 
valve li

Inlet opens

1° before TDC

1° before TDC

Inlet closes

29° after BDC

29° after BDC

Exhaust opens

28° before BDC

28° before BDC

Exhaust closes

16° before TDC

16° before TDC

Tolerance ± 3°

Tolerance ± 3°

Valve head dia.

Inlet

mm (in) 32 (1.25984)

36 (1.4173)

Exhaust

mm (in) 27 (1.06299)

31(1.2205)

from 1996 mod. year on

Inlet

mm (in)

34 (1.3386)

Exhaust

mm (in)

29 (1.1417)

Stem dia.

Inlet

mm (in) 4.966...4.980 

(0.16551...0.19606)

5.960...5.975 
(0.23465...0.23524)

Wear limit

mm (in) 4.946 (0.19472)

5.940 (0.23386)

Exhaust

mm (in) 4.956..4.970 

(0.19512...0.19567)

5.945...5.960 
(0.23406...0.23465)

Wear limit

mm (in) 4.936 (0.19433)

5.925 (0.23327)

from 1996 mod. year on

Inlet

mm (in)

4.966...4.980 
(0.16551...0.19606)

Wear limit

mm (in)

4.946 (0.19472)

Exhaust

mm (in)

4.956..4.970 
(0.19512...0.19567)

Wear limit

mm (in)

4.936 (0.19433)

Valve head edge thickness

Inlet

mm (in) 1.00 

± 0.2

 

(0.03937 

± 0.00787

)

1.00 

± 0.2

 

(0.03937 

± 0.00787

)

Wear limit

mm (in) 0.5 (0.01969)

0.5 (0.01969)

Exhaust

mm (in) 1.00 

± 0.2

 

(0.03937 

± 0.00787

)

1.65 

± 0.2

 

(0.06496 

± 0.00787

)

Wear limit

mm (in) 0.5 (0.01969)

1.0 (0.03937)

from 1996 mod. year on

Inlet

mm (in)

1.00 

± 0.2

(0.03937 

± 0.00787

)

Wear limit

mm (in)

0.5 (0.01969)

Exhaust

mm (in)

1.00 

± 0.2

(0.03937 

± 0.00787

)

Wear limit

mm (in)

0.5 (0.01969)

Max. runout of valve head at valve seat

Inlet, exhaust

mm (in) 0.035 (0.001378)

0.035 (0.001378)

Technical Data

R 850 GS

R 1100 GS

11.23

Valve seat ring

Valve seat angle

Inlet

45°

45°

Exhaust

45°

30°

from 1996 mod. year on

Inlet

45°

Exhaust

45°

Valve seat width

Inlet

mm (in) 1.1 

± 0.15

 

(0.04331 

± 0.00591

)

1.1 

± 0.15

 

(0.04331 

± 0.00591

)

Wear limit

mm (in) 2.5 (0.09843)

2.5 (0.09843)

Exhaust

mm (in) 1.4

 ± 0.15

(0.05512 

± 0.00591

)

1.4

 ± 0.15

(0.05512 

± 0.00591

)

Wear limit

mm (in) 3.0 (0.11811)

3.0 (0.11811)

Valve seat extl. dia. (dimension for valve seat 
machining)

Inlet

mm (in) 31.4 

± 0.1

(1.23622 

± 0.003937

)

35.2 

± 0.1

 

(1.38583 

± 0.003937

)

Exhaust

mm (in) 26.4 

± 0.1

(1.03937 

± 0.003937

)

30.3 

± 0.1

 

(1.19291 

± 0.00393

)

from 1996 mod. year on

Inlet

mm (in)

33.4 

± 0.1

 

(1.31496 

± 0.00393

)

Exhaust

mm (in)

28.4 

± 0.1

 

(1.11811 

± 0.00393

)

Seat ring dia. (oversize +0.2 mm)

Inlet

mm (in) 34.634...34.650 

(1.36254...1.36417)

37.634...37.650 
(1.48165...1.48228)

Exhaust

mm (in) 30.134...30.150 

(1.186378...1.18701)

34.134...34.150 
(1.34386...1.34449)

from 1996 mod. year on

Inlet

mm (in)

36.617...36.633 
(1.44161...1.44224)

Exhaust

mm (in)

32.134...32.150 
(1.26512...1.26575)

Seat dia. in cylinder head (oversize +0.2 mm)

Inlet

mm (in) 34.500...34.525 

(1.358268...1.359252)

37.500...37.525 
(1.47638...1.47736)

Exhaust

mm (in) 30.000...30.025 

(1.1811...1.18209)

34.000...34.025 
(1.33859...1.33957)

from 1996 mod. year on

Inlet

mm (in)

36.500...36.525 
(1.43701...1.43799)

Exhaust

mm (in)

32.000...32.025 
(1.25984...1.26083)

Technical Data

R 850 GS

R 1100 GS

11.24

Valve guide

Valve guide

Extl. dia.

mm (in) 12.533...12.544 

(0.49343...0.49386)

12.533...12.544 
(0.49343...0.49386)

Bore in cylinder head

mm (in) 12.500...12.518 

(0.49213...0.49283)

12.500...12.518 
(0.49213...0.49283)

Overlap

mm (in) 0.015...0.044 

(0.00059...0.001732)

0.015...0.044 
(0.00059...0.001732)

Repair stages

Replacement valve guide Extl. dia.

mm (in) 12.550...12.561 

(0.49409...0.49453)

12.550...12.561 
(0.49409...0.49453)

Oversize valve guide

Extl. dia.

mm (in) 12.733...12.744 

(0.501299...0.501732)

12.733...12.744 
(0.501299...0.501732)

Valve guide

Intl. dia

mm (in) 5.0...5.012 

(0.19685...0.19732)

6.0...6.015 
(0.23622...0.23681)

Radial clearance

Inlet

mm (in) 0.020...0.046 

(0.000787...0.001811)

0.025...0.055 
(0.000984...0.002165)

Wear limit

mm (in) 0.15 (0.00591)

0.15 (0.00591)

Exhaust

mm (in) 0.030...0.056 

(0.0011811...0.002205)

0.040...0.070 
(0.001575...0.002756)

Wear limit

mm (in) 0.17 (0.006693)

0.17 (0.006693)

from 1996 mod. year on

Valve guide

Intl. dia

mm (in)

5.0...5.012 
(0.19685...0.19732)

Radial clearance

Inlet

mm (in)

0.020...0.046 
(0.000787...0.001811)

Wear limit

mm (in)

0.15 (0.00591)

Exhaust

mm (in)

0.030...0.056 
(0.0011811...0.002205)

Wear limit

mm (in)

0.17 (0.006693)

Valve spring

Spring length, 

off-load

mm (in) 41.1 (1.61811)

41.1 (1.61811)

Wear limit

mm (in) 39.0 (1.53543)

39.0 (1.53543)

Rocker

Bore dia.

mm (in) 16.016...16.027 

(0.63055...0.63984)

16.016...16.027 
(0.63055...0.63984)

Rocker shaft dia.

mm (in) 15.973...15.984 

(0.62886...0.62929)

15.973...15.984 
(0.62886...0.62929)

Radial clearance

mm (in) 0.032...0.054 

(0.001259...0.002126)

0.032...0.054 
(0.001259...0.002126)

Wear limit

mm (in) 0.1 (0.003937)

0.1 (0.003937)

Axial play

min.

mm (in) 0.05 (0.001969)

0.05 (0.001969)

max.

mm (in) 0.40 (0.01575)

0.40 (0.01575)

Technical Data

R 850 GS

R 1100 GS

11.25

Camshaft

Opening angle, inlet/exhaust cams

300°/284°

300°/284°

Cam spread, inlet/exhaust

103°/112°

103°/112°

Marking

Marking in position 1

Marking in position 1

Inlet valve lift

mm (in) 9.68 (0.3811)

(valve clearance = 0)

9.68 (0.3811) 
(valve clearance = 0)

Exhaust valve lift

mm (in) 8.55 (0.33661) 

(valve clearance = 0)

8.55 (0.33661)
(valve clearance = 0)

Camshaft bearing bore dia.

mm (in) 21.02...21.04 

(0.82756...0.828346)

21.02...21.04 
(0.82756...0.828346)

Camshaft dia.

mm (in) 20.97...21.00 

(0.82559...0.82677)

20.97...21.00 
(0.82559...0.82677)

Radial clearance

mm (in) 0.02...0.07 

(0.000787...0.0027559)

0.02...0.07 
(0.000787...0.0027559)

Wear limit

mm (in) 0.15 (0.0059055)

0.15 (0.0059055)

Width of guide bearing

mm (in) 15.92...15.95 

(0.62677...0.62795)

15.92...15.95 
(0.62677...0.62795)

Width of camshaft bearing

mm (in) 16.0...16.05 

(0.62992...0.6318897)

16.0...16.05 
(0.62992...0.6318897)

Axial play

mm (in) 0.08...0.13 

(0.0031496...0.005118)

0.08...0.13 
(0.0031496...0.005118)

Wear limit

mm (in) 0.25 (0.0098425)

0.25 (0.0098425)

Bucket-type tappet

Extl. dia.

mm (in) 23.947...23.960 

23.947...23.960 

Bore dia. in cylinder head

mm (in) 24.000...24.021 

(0.94488...0.94571)

24.000...24.021 
(0.94488...0.94571)

Radial clearance

mm (in) 0.040...0.074 

(0.00175...0.002913)

0.040...0.074 
(0.00175...0.002913)

Wear limit

mm (in) 0.18 (0.0070866)

0.18 (0.0070866)

Auxiliary shaft

Bore dia. in crankcase

front/back

mm (in) 25.020...25.041 

(0.98504...0.985866)

25.020...25.041 
(0.98504...0.985866)

Auxiliary shaft dia.

front/back

mm (in)

24.959...24.980 
(0.98264...0.98346)

24.959...24.980 
(0.98264...0.98346)

Radial clearance

mm (in) 0.040...0.082 

(0.001575...0.003228)

0.040...0.082 
(0.001575...0.003228)

Wear limit

mm (in) 0.17 (0.006693)

0.17 (0.006693)

Technical Data

R 850 GS

R 1100 GS

11.26

Crankshaft

Marking of main bearing and crankpin on 
front crank web

no paint mark

Grinding stage 0

Grinding stage 0

paint mark

Grinding stage1
(-0.25mm (-0.009843))

Grinding stage 1
(-0.25mm (-0.009843))

Grinding stage 0 (grinding stg. 1=—0.25mm)

Guide bearing bore dia.

mm (in) 64.949...64.969 

(2.557047...2.557834)

64.949...64.969 
(2.557047...2.557834)

Guide bearing dia.

mm (in) Green: 

59.964...60.003 
(2.36079...2.36232)

Green: 
59.964...60.003 
(2.36079...2.36232)

Yellow: 59.974...60.013 
(2.36118...2.36272)

Yellow: 59.974...60.013 
(2.36118...2.36272)

Main bearing journal dia.

mm (in) Green: 

59.939...59.948 
(2.35980...2.360157)

Green: 
59.939...59.948 
(2.35980...2.360157)

Yellow: 59.949...59.958 
(2.360197...2.36055)

Yellow: 59.949...59.958 
(2.360197...2.36055)

Radial clearance

mm (in) 0.016...0.064 

(0.0006299..0.002519)

0.016...0.064 
(0.0006299..0.002519)

Wear limit

mm (in) 0.1 (0.003937)

0.1 (0.003937)

Main bearing bore dia.

mm (in) 60.000...60.019 

(2.3622...2.36295)

60.000...60.019 
(2.3622...2.36295)

Main bearing dia.

mm (in) Green: 

54.998...55.039 
(2.16528...2.16689)

Green: 
54.998...55.039 
(2.16528...2.16689)

Yellow: 55.008...55.049 
(2.16567...2.16728)

Yellow: 55.008...55.049 
(2.16567...2.16728)

Main bearing journal dia.

mm (in) Green: 

54.971...54.980 
(2.1642...2.164567)

Green: 
54.971...54.980 
(2.1642...2.164567)

Yellow: 54.981...54.990 
(2.16461...2.16496)

Yellow: 54.981...54.990 
(2.16461...2.16496)

Radial clearance

mm (in) 0.018...0.068 

(0.0001086....002677)

0.018...0.068 
(0.0001086....002677)

Wear limit

mm (in) 0.13 (0.005118)

0.13 (0.005118)

Width of guide bearing

mm (in) 24.890...24.940 

(0.97992...0.98189)

24.890...24.940 
(0.97992...0.98189)

Bearing width of main bearing journal

mm (in) 25.020...25.053 

(0.98504...0.986339)

25.020...25.053 
(0.98504...0.986339)

Axial play

mm (in) 0.080...0.163 

(0.0031496...0.006417)

0.080...0.163 
(0.0031496...0.006417)

Wear limit

mm (in) 0.2 (0.007874)

0.2 (0.007874)

Grinding stage 0 (grinding stg. 1 = –0.25mm)

Crankpin dia.

mm (in) 47.975...47.991 

(1.88878...1.88941)

47.975...47.991 
(1.88878...1.88941)

Bearing width of crankpin

mm (in) 22.065...22.195 

(0.86870...0.87381)

22.065...22.195 
(0.86870...0.87381)

Technical Data

R 850 GS

R 1100 GS

11.27

Connecting rod

Big end bore dia.

mm (in) 51.000...51.013 

(2.00787...2.008386)

51.000...51.013 
(2.00787...2.008386)

Big end bearing dia.

mm (in) 48.016...48.050 

(1.89039...1.89173)

48.016...48.050 
(1.89039...1.89173)

Radial clearance

mm (in) 0.025...0.075 

(0.000984...0.0029527)

0.025...0.075 
(0.000984...0.0029527)

Wear limit

mm (in) 0.13 (0.001118)

0.13 (0.001118)

Width of big end bearing eye

mm (in) 21.883...21.935 

(0.86154...0.86358)

21.883...21.935 
(0.86154...0.86358)

Conrod end float

mm (in) 0.130...0.312 

(0.005118...0.0122834)

0.130...0.312 
(0.005118...0.0122834)

Wear limit

mm (in) 0.5 (0.019685)

0.5 (0.019685)

Small end bearing bore dia.

mm (in) 22.015...22.025 

(0.86673...0.867126)

22.015...22.025 
(0.86673...0.867126)

Radial clearance

mm (in) 0.015...0.030 

(0.0005905...0.0018)

0.015...0.030 
(0.0005905...0.0018)

Wear limit

mm (in) 0.06 (0.0023622)

0.06 (0.0023622)

Distance between centers

mm (in) 125 (4.92126)

125 (4.92126)

Max. deviation from parallel of conrod bores 
at 150 mm spacing

mm (in) 0.07 (0.0027559)

0.07 (0.0027559)

Cylinders

Bore

20 mm (0.7874 in)
from top edge

20 mm (0.7874 in)
from top edge

A

mm (in) 87.492...87.500 

(3.444567...3.44489)

98.992...99.000 
(3.89732...3.897638)

Wear limit

mm (in) 87.550 (3.44685)

99.050 (3.899606)

B

mm (in) 87.500...87.508 

(3.44489...3.4452)

99.000...99.008 
(3.897638...3.897953)

Wear limit

mm (in) 87.558 (3.447165)

99.058 (3.899921)

Total wear clearance of piston and cylinder

mm (in) 0.12 (0.0047244)

0.12 (0.0047244)

Permitted out-of-roundness of cylinder bore

20 mm from the top edge

mm (in) 0.03 (0.0011811)

0.03 (0.0011811)

100 mm from the lower edge

mm (in) 0.04 (0.0015748)

0.04 (0.0015748)

Pistons

Piston dia.

(Measuring plane A — 

a

 see Checking pistons 

and cylinders)

A

mm (in) 87.465...87.477 

(3.4435...3.443977)

98.965...98.977 
(3.89626...3.896732)

Wear limit

mm (in) 87.390 (3.44055)

98.890 (3.8933)

B

mm (in) 87.477...87.485 

(3.443976...3.44429)

98.977...98.989 
(3.896732...3.897204)

Wear limit

mm (in) 87.400 (3.4409448)

98.900 (3.8937)

AB

mm (in) 87.473...87.481 

(3.44382...3.444134)

98.973...98.981 
(3.89657...3.8968897)

Wear limit

mm (in) 87.395 (3.44075)

98.895 (3.8935039)

Installed clearance

mm (in) 0.011...0.035 

(0.000433...0.0013779)

0.011...0.035 
(0.000433...0.0013779)

Total wear clearance of piston and cylinder

mm (in) 0.12 (0.0047244)

0.12 (0.0047244)

Technical Data

R 850 GS

R 1100 GS