BMW R models 1970-1985 Engine Technical specs

Engine

Type:

Air - cooled horizontally - opposed transverse twin, with pushrod operated overhead valves

Dimensions

 

Bore

Stroke

Capacity - Actual

 

R45

70.0mm (2.76")

61.5mm (2.42")

473.1cc (28.86 cu in)

 

R50

67.0mm (2.64")

70.6mm (2.78")

497.6cc (30.35 cu in)

 

R60

73.5mm (2.89")

70.6mm (2.78")

598.8cc (36.53 cu in)

 

R65, R65LS

82.0mm (3.23")

61.5mm (2.42")

649.2cc (39.60 cu in)

 

R75

82.0mm (3.23")

70.6mm (2.78")

745.3cc (45.46 cu in)

 

All 800cc models

84.8mm (3.34")

70.6mm (2.78")

797.1cc (48.62 cu in)

 

R90/6, R90S

90.0mm (3.54")

70.6mm (2.78")

897.8cc (54.77 cu in)

 

All 1000cc models

94.0mm (3.70")

70.6mm (2.78")

979.4cc (59.74 cu in)

Compression ratio

(standard values quoted, some machines may have been fitted with compression plates to reduce compression ratio from standard)

 

R45

9.2 : 1

  
 

R50

8.6 : 1

  
 

R60

9.2 : 1

  
 

R65, R65LS

9.2 : 1

  
 

R75

9.0 : 1

  
 

R80/7 - 40 kw version

9.2 : 1

  
 

R80/7 - 37 kw version, all other 800cc models

8.2 : 1

  
 

R90/6

9.0 : 1

  
 

R90S

9.5 : 1

  
 

R100/7

9.0 : 1

  
 

R100 (UK)

8.2 : 1

  
 

All other 1000cc models*

9.5 : 1

  

*All US machines from 1980 models onwards, compression ratio was reduced to 8.2:1.

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Recommended engine speeds - rpm:

 

 

Idle

Max. permissible continuous

Max. permissible

 
 

R45 R65 R65LS

800 - 1100

7300

7650

 

R50 R60/5 R60/6 R75/5 R75/6 R90/6

600 - 800

6500

7000

 

R60/7

800 - 1100

6500

7200

 

R75/7

800 - 1100

6500

7400

 

All 800cc models

800 - 1100

7200

7400

 

R90S

600 - 800

7000

7300

 

R100/7

800 - 1100

6800

7400

 

All other 1000cc models - UK - all R100T R100S 1977,78 - US - all except below

800 - 1100

7000

7400

 

All other 1000cc models - UK - all except those above - US - R100RS 1977

800 - 1100

7200

7400

Claimed engine output - DIN:

 

Max. power (kw/hp @ rpm)

Max. torque (Nm/lbf ft @ rpm)

 
 

R45

26/35 @ 7250

37.4/27.6 @ 5500

 
 

R50

24/32 @ 6400

38.3/28.3 @ 5000

 
 

R60

29/40 @ 6400

48.1/35.5 @ 5000

 
 

R65 1978 - 80 models*

33/45 @ 7250

50.0/36.9 @ 5500

 
 

R65 1981 on models, R65LS*

37/50 @ 7250

52.3/38.6 @ 6500

 
 

R75

37/50 @ 6200

58.8/43.4 @ 5000

 
 

R80/7 - high comp. version

40/55 @ 7000

62.5/46.1 @ 5500

 
 

R80/7 - low comp. version

37/50 @ 7250

56.6/41.8 @ 5500

 
 

R80G/S R80ST*

37/50 @ 6500

56.7/41.9 @ 5000

 
 

R80RT 1983, 84 models*

37/50 @ 6500

59.0/43.5 @ 3500

 
 

R80, R80RT 85 on models*

37/50 @ 6500

58.0/42.8 @ 4000

 
 

R90/6

44/60 @ 6500

73.0/53.9 @ 5500

 
 

R90S

49/67 @ 7000

76.0/56.1 @ 5500

 
 

R100/7

44/60 @ 6500

73.5/54.2 @ 4000

 
 

R100T - US*

44/60 @ 6500

74.6/55.1 @ 5500

 
 

R100T - UK, R100S - UK '77, '78 R100S - US, R100RS - US '78, '79, R100RT - US*

48/65 @ 6600

75.0/55.4 @ 5500

 
 

R100 - UK

49/67 @ 7000

72.0/53.1 @ 5500

 
 

R100S - UK '79, '80, R100RS - UK '77 - '80, R100RT - UK '79, '80 R100RS - US '77*

51/70 @ 7250

76.0/56.1 @ 5500

 
 

R100CS R100RS R100RT - UK models '81 on*

51/70 @ 7000

76.0/56.1 @ 6000

 

*All models 1980 on - information applies only to UK models, not available for US models.

Direction of engine rotation

clockwise, looking from front of machine

Compression pressure

R80G/S R80ST R80RT R80 '85 on

All other models

 
 

Good

over 9.0bar (131psi)

over 10.0bar (145psi)

 
 

Normal

7.5 - 9.0bar (109 - 131psi)

8.5 - 10.0bar (123 - 145psi)

 
 

Poor

below 7.5bar (109psi)

below 8.5bar (123psi)

 

Valve clearances - engine cold

Normal

 

First 1000km (600m)

 
 

Inlet

Exhaust

Inlet

Exhaust

/5,/6

0.15mm (.006")

0.20mm (.008")

N/Av

N/Av

/7, R80G/S, R80ST, R80RT '83 - 84

0.10mm (.004")

0.15mm (.006")

0.15mm (.006")

0.20mm (.008")

R45, R65, R65LS, R80, R80RT '85 on

0.10mm (.004")

0.20mm (.008")

0.25mm (.010")

Valve timing

with 2.0mm (.08") valve clearance, tolerance of + - 2.5 degrees.

   

R50/5 R60/5 R60/6 up to 1975

R60/6 '76 R60/7 '77

R60/7 '78

 

Inlet opens

40 deg ATDC

TDC

6 deg BTDC

 

Inlet closes

40 deg ABDC

40 deg ABDC

34 deg ABDC

 

Exhaust opens

40 deg BBDC

40 deg BBDC

46 deg BBDC

 

Exhaust closes

40 deg BTDC

TDC

6 deg BTDC

 

All R75 & R90, R100/7 R100S R100RS '77

R80/7 R100/7 R100S R100RS '78

All other models

 
 

Inlet opens

10 deg BTDC

16 deg BTDC

16 deg BTDC

 

Inlet closes

50 deg ABDC

44 deg ABDC

44 deg ABDC

 

Exhaust opens

50 deg BBDC

56 deg BBDC

56 deg BBDC

 

Exhaust closes

10 deg BTDC

4 deg BTDC

4 deg ATDC

Valves

 

Head diameter:

Inlet

Exhaust

 
 

R45 R50

34mm (1.34")

32mm (1.26")

 
 

R60 R65 up to '80

38mm (1.50")

34mm (1.34")

 
 

R65 '81 on, R65LS

40mm (1.58")

36mm (1.42")

 
 

R75, all 800cc models

42mm (1.65")

38mm (1.50")

 
 

R90/6 R90S R100/7

42mm (1.65")

40mm (1.58")

 
 

All other 1000cc models

44mm (1.73")

40mm (1.58")

 
 

Head rim minimum thickness:

     
 

/5 /6 /7

1.0mm (0.0394")

1.0mm (0.0394")

 
 

R80G/S R80ST R80RT '83 - '84

0.8mm (0.0315")

0.8mm (0.0315")

 
 

R45 R65 R65LS

1.0 - 1.5mm (0.0394 - 0.0591")

1.0 - 1.2mm (0.0394 - 0.0472")

 
 

Head maximum runout:

     
 

/5 /6 /7

0.025mm (0.0010")

0.025mm (0.0010")

 
 

R80G/S R80ST R80RT '83 - 84

0.020mm (0.0008")

0.020mm (0.0008")

 
 

Overall length:

     
 

R50/5

102.6 - 103.0mm

102.1 - 102.5mm

 
 

(4.0394 - 4.0551")

(4.0197 - 4.0354")

   

R45 R65 R65LS

98.8 - 100.2mm

99.1 - 99.5mm

 
 

(3.8898 - 3.9449")

(3.9016 - 3.9173")

   
 

R60/5 R60/6

98.2 - 98.5mm

97.2 - 97.5mm

 
 

(3.8661 - 3.8780")

(3.8268 - 3.8386")

   
 

R60/7

99.2 - 99.5mm

98.2 - 98.5mm

 
 

(3.9055 - 3.9173")

(3.8661 - 3.8780")

   
 

All other models

98.4 - 98.8mm

98.4 - 98.8mm

 
 

(3.8740 - 3.8898")

(3.8740 - 3.8898")

   

Valve Guides

 

Length overall:

     
 

/5 /6 except R90S

54mm (2.1260")

 
 

R90S, /7

48mm (1.8898")

   
 

R45 R65 R65LS

45mm (1.7717")

   
 

R80G/S R80ST R80RT '83 - '84

44mm (1.7323")

   
 

Outside diameter:

     
 

/5 /6 /7 R80G/S R80ST R80RT '83 - 84

14.050 - 14.061mm (0.5532 - 0.5536")

   
 

R45 R65 R65LS

14mm (0.5512")

   
 

Inside diameter:

     
 

/5 /6 /7

8mm (0.3150")

   
 

R45 R65 R65LS

7mm (0.2756")

   
 

R80G/S R80ST R80RT '83 - 84

8.000 - 8.015mm (0.3150 - 0.3156")

   
 

Bore in cylinder head:

     
 

/5 /6 /7 R45 R65 R65LS

14mm (0.5512")

   
 

R80G/S R80ST R80RT '83 - 84

14.000 - 14.018mm (0.5512 - 0.5519")

   
 

Interference fit in cylinder head:

     
 

/5 /6 /7

0.032 - 0.061mm (0.0013 - 0.0024")

 
 

All other models

N/Av

   
 

Oversizes available

0.1 & 0.2mm (0.004 & 0.008")

   
 

Valve stem / guide standard clearance:

Inlet

Exhaust

 
 

R50/5

0.040 - 0.070mm

0.050 - 0.080mm

 
 

(0.0016 - 0.0028")

(0.0020 - 0.0032")

   
 

R45 R65 R65LS

0.025 - 0.055mm

0.040 - 0.070mm

 
 

(0.0010 - 0.0022")

(0.0016 - 0.0028")

   
 

R60

0.050 - 0.080mm

0.065 - 0.095mm

 
 

(0.0020 - 0.0032")

(0.0026 - 0.0037")

   
 

All other models

0.050 - 0.080mm

0.050 - 0.080mm

 
 

(0.0020 - 0.0032")

(0.0020 - 0.0032")

   

Inlet and exhaust valve stem / guide max. permissible clearance - measured at top of guide:

 

R45 R65 R65LS

0.10mm (0.0039")

   
 

All other models

0.15mm (0.0059")

   

Valve seats

 

Outside diameter:

Inlet

Exhaust

 
 

R50/5

36.175 - 36.200mm

36.140 - 36.150mm

 
   

(1.4242 - 1.4252")

(1.4228 - 1.4232")

 
 

R45

36.2mm (1.4252")

36.2mm (1.4252")

 
 

R60

39.175 - 39.200mm

39.175 - 39.200mm

 
   

(1.5423 - 1.5433")

(1.5423 - 1.5433")

 
 

R65 R65LS

39.2mm (1.5433")

39.2mm (1.5433")

 
 

R75/5

43.175 - 43.200mm

43.140 - 43.150mm

 
   

(1.6998 - 1.7008")

(1.6984 - 1.6988")

 
 

R75/6 R90/6 R90S

43.175 - 43.200mm

43.175 - 43.200mm

 
   

(1.6998 - 1.7008")

(1.6998 - 1.7008")

 
 

R75/7 R80/7 R100/7

43.175 - 43.200m

43.134 - 43.200mm

 
   

(1.6998 - 1.7008")

(1.6982 - 1.7008")

 
 

R80G/S R80ST R80RT '83 - 84

43.175 - 43.200m

43.134 - 43.150mm

 
   

(1.6998 - 1.7008")

(1.6982 - 1.6988")

 
 

All other 1000cc models

45.175 - 45.200mm

45.175 - 45.200mm

 
   

(1.7785 - 1.7795")

(1.7785 - 1.7795")

 
 

Bore in cylinder head - inlet and exhaust:

     
 

R50/5

36.00 - 36.025mm (1.4173 - 1.4183")

   
 

R45

36mm (1.4173")

   
 

R60

39.00 - 39.025mm (1.5354 - 1.5364")

   
 

R65, R65LS

39mm (1.5354")

   
 

All 745cc 800cc 900cc, R100/7

43.000 - 43.025mm (1.6929 - 1.6939")

   
 

All other 1000cc models

45.000 - 45.025mm (1.7717 - 1.7727")

   
 

Interference fit in cylinder head:

Inlet

Exhaust

 
 

R50/5 R75/5

0.150 - 0.200mm (0.0059 - 0.0079")

0.115 - 0.150mm (0.0045 - 0.0059")

 
 

R45 R65 R65LS

N/Av

N/Av

 
 

R75/7 R80/7 R100/7 R80G/S R80ST

     
 

R80RT '83 - '84

0.150 - 0.200mm (0.0059 - 0.0079")

0.109 - 0.150mm (0.0043 - 0.0059")

 
 

All other models

0.150 - 0.200mm (0.0059 - 0.0079")

0.150 - 0.200mm (0.0059 - 0.0079")

 
 

Seat angle:

     
 

Main seating face

45 deg

   
 

At combustion chamber

15 deg

   
 

At inlet/exhaust port

75 deg

   
 

Seat width:

     
 

Inlet

1.5mm (0.0591")

   
 

Exhaust

2.0mm (0.0787")

   
 

Seat oversizes available

0.2 0.4mm (0.0079 0.0168")

   

Valve springs

 

Wire thickness

4.25mm (0.1673")

   
 

Spring free length - approx:

     
 

Blue or green code

43.5mm (1.7126")

   
 

Brown code

46.0mm (1.811")

   
 

Spring force at test length:

     
 

At 37.6mm (1.4803")

27.84 - 30.16 kp (61.30 - 66.5 lb)

   
 

At 28.5mm (1.1221")

70.00 - 72.80 kp (154.30 - 160.5 lb)

   

Rocker gear

 

Arm ID - /5

18.032 - 18.059mm (0.7099 - 0.7110")

   
 

Bush OD - /5

18.012 - 18.030mm (0.7091 - 0.7098")

   
 

Arm/bush clearance - /5

0.002 - 0.047mm (0.00008 - 0.00185")

   
 

Bush ID /5

14.532 - 14.559mm (0.5721 - 0.5732")

   
 

Shaft OD /5

14.512 - 14.530mm (0.5713 - 0.5720")

   
 

Bush / shaft clearance /5

0.002 - 0.047mm (0.00008 - 0.00185")

   
 

Arm axial float:

     
 

R80 R80RT 1985

0.03 - 0.07mm (0.0012 - 0.0028")

   
 

All other models

Nil, but arm must be free to move

   

Camshaft drive chain

 

Type:

     
 

/5 /6 /7 up to 1978

Duplex roller chain

   
 

All other models

Single row chain

   
 

Size

3/8 x 7/32"

   
 

Number of links

50

   

Camshaft

 

Front (alternator end) bearing bore

40.000 - 40.039mm (1.5748 - 1.5763")

   
 

Front flange bearing OD

39.984 - 40.000mm (1.5742 - 1.5748")

   
 

Front flange bearing ID

25.000 - 25.013mm (0.9843 - 0.9848")

   
 

Camshaft front bearing journal OD

24.967 - 24.980mm (0.9830 - 0.9835")

   
 

Camshaft radial clearance - at front bearing

0.020 - 0.046mm (0.0008 - 0.0018")

   
 

Rear (flywheel end) bearing bore

24.000 - 24.021mm (0.9449 - 0.9457")

   
 

Camshaft rear bearing journal OD

23.967 - 23.980mm (0.9436 - 0.9441")

   
 

Camshart radial clearance - at rear bearing

0.020 - 0.054mm (0.0008 - 0.0021")

   
 

Camshaft end float

0.080 - 0.120mm (0.0032 - 0.0047")

   
 

Base circle

28mm (1.1024")

   
 

Cam lift:

     
 

R50/5 R60

6.198mm (0.2440")

   
 

All other models

6.756mm (0.2660")

   
         
 

Maximum permissible runout of ATU shaft - /5 /6 /7 up to '78

0.02mm (0.0008")

   

Cam followers and pushrods

 

OD

21.955 - 21.975mm (0.8644 - 0.8652")

   
 

Crankcase ID

21.985 - 22.006mm (0.8656 - 0.8664")

   
 

Follower / crankcase clearance:

     
 

Standard

0.010 - 0.051mm (0.0004 - 0.0020")

   
 

Service limit

0.075mm (0.0030")

   
 

Pushrod length:

     
 

R45 R65 R65LS /5 /6 up to '75

N/Av

   
 

All other models

274.7 - 275.3mm (10.8149 - 10.8386")

   

Crankshaft and main bearings

 

Journal dimensions

Basically the same, but tolerances vary according to model and year.

   
 

Main bearing bushes dimensions and radial clearances.

Selective fit depending on journal

   
 

Main bearing journal/bush clearance:

 

R45 (UK), R65 (UK), R65LS (UK), all /5 /6 /7

0.035 - 0.065mm (0.0014 - 0.0025")

   
 

/7 '81 on, R80G/S, R80ST, R65 (US), R65LS (US) - red size bush

0.017 - 0.066mm (0.0007 - 0.0026")

   
 

/7 '81 on, R80G/S, R80ST, R65 (US), R65LS (US) - blue size bush

0.019 - 0.067mm (0.0008 - 0.0026")

   
 

Crankshaft regrind stages:

     
 

1st

0.25mm (0.0100")

   
 

2nd

0.50mm (0.0200")

   
 

3rd

0.75mm (0.0300")

   
 

Max. runout - at front main bearing journal

0.02mm (0.0008")

   
 

Max. lateral runout at flywheel

0.10mm (0.0008")

   
 

Crankshaft standard endfloat

0.08 - 0.15mm (0.0032 - 0.0059")

   
 

Thrust washer thickness:

     
 

Standard - red

2.483 - 2.530mm (0.0978 - 0.0996")

   
 

Standard - blue

2.530 - 2.578mm (0.0996 - 0.1015")

   
 

Standard - green

2.578 - 2.626mm (0.1015 - 0.1034")

   
 

Standard - yellow

2.626 - 2.673mm (0.1034 - 0.1052")

   
 

Wear limit - all

minus 0.20mm (0.0079")

   

Connecting rods and bearings

 

Crankpin standard OD

47.975 - 47.991mm (1.8888 - 1.8894")

   
 

Crankpin regrind stages:

     
 

1st

0.25mm (0.0100")

   
 

2nd

0.50mm (0.0200")

   
 

3rd

0.75mm (0.0300")

   
 

Connecting rod big - end ID - less bearing shells:

 

/5, /6, /7 1977

52.000 - 52.010mm (2.0472 - 2.0476")

   
 

All other models

52.000 - 52.015mm (2.0472 - 2.0478")

   
 

Con. rod radial clearance

0.023 - 0.069mm (0.0009 - 0.0027")

   
 

Con. rod big - end width

21.883 - 21.935mm (0.8615 - 0.8636")

   
 

Crankpin width

22.065 - 22.149mm (0.8657 - 0.8720")

   
 

Con. rod axial clearance (endfloat):

     
 

Standard

0.130 - 0.266mm (0.0051 - 0.105")

   
 

Max. permissible

0.320mm (0.0126")

   
 

Max. weight difference between con. rods:

     
 

/5, /6

6 grams (0.2116 oz)

   
 

/7, R45, R65, R65LS

3 grams (0.1058 oz)

   
 

R80G/S, R80ST

2 grams (0.0705 oz)

   
 

Con. rod small - end ID - less bush

24.000 - 24.021mm (0.9449 - 0.9457")

   
 

Small - end bush OD

24.060 - 24.100mm (0.9472 - 0.9488")

   
 

Small - end bush ID:

     
 

Standard

22.015 - 22.020mm (0.8667 - 0.8669")

   
 

Max. permissible

22.040mm (0.8677")

   
 

Gudgeon pin/small - end bush clearance:

 

/5,/6,/7 up to '80 - white coded pin

0.015 - 0.023mm (0.0006 - 0.0009")

   
 

/5,/6,/7 up to '80 - black coded pin

0.018 - 0.026mm (0.0007 - 0.0010")

   
 

/7 '81 on, R80G/S, R80ST

0.015 - 0.024mm (0.0006 - 0.0009")

   
 

R45, R65, R65LS

0.015 - 0.025mm (0.0006 - 0.0009")

   
 

Gudgeon pin OD:

 

/5,/6,/7 up to '80 - white coded pin

21.997 - 22.000mm (0.8660 - 0.8661")

   
 

/5,/6,/7 up to '80 - black coded pin

21.994 - 21.997mm (0.8659 - 0.8660")

   
 

/7 '81 on, R80G/S, R80ST

21.996 - 22.000mm (0.8659 - 0.8661")

   
 

R45, R65, R65LS

21.995 - 22.000mm (0.8659 - 0.8661")

 
 

Gudgeon pin bore ID - in piston:

 

/5,/6,/7 up to '80 - white code (W stamped in piston crown)

22.000 - 22.003mm (0.8661 - 0.8662")

   
 

/5,/6,/7 up to '80 - black code (S stamped in piston crown)

21.997 - 22.000mm (0.8660 - 0.8661")

   
 

/7 '81 on, R80G/S, R80ST

22.000 - 22.004mm (0.8661 - 0.8663")

   
 

R45

22.002 - 22.007mm (0.8662 - 0.8664")

   
 

R65, R65LS

22.005 - 22.010mm (0.8663 - 0.8665")

   
 

Gudgeon pin/piston clearance:

 

/5,/6,/7 up to '80

0.000 - 0.006mm (0.0000 - 0.0002")

   
 

/7 '81 on, R80G/S, R80ST

0.000 - 0.008mm (0.0000 - 0.0003")

   
 

R45

0.002 - 0.012mm (0.0001 - 0.0005")

   
 

R65, R65LS

0.005 - 0.015mm (0.0002 - 0.0006")

   

Cylinders

 

Type:

     
 

All models up to 1980 finned jacket by 'Al-Fin' process

Cast iron sleeve joined to aluminium alloy

   
 

R45, R65, R65LS '81 on

Aluminium alloy barrel with 'Nikasil' plated bore

   
 

1000cc and 800cc, '81 on

Aluminium alloy barrel with 'Galnikal' plated bore

   
 

Cylinder standard bore ID - at specified bore size code:

 

A

B

C

 
 

R50/5

67.000mm

67.010mm

67.020mm

 

(2.7368")

(2.6382")

(2.6386")

 
 

R45

69.995 - 70.005mm

70.005 - 70.015mm

70.015 - 70.025mm

 

(2.7557 - 2.7561") (2.7561 - 2.7565") (2.7565 - 2.7569")

     
 

R60/5, R60/6

73.500mm

73.510mm

73.520mm

 

(2.8937")

(2.8941")

(2.8945")

 
 

R60/7

73.500 - 73.510mm

73.510 - 73.520mm

73.520 - 73.530mm

 

(2.8937 - 2.8941") (2.8941 - 2.8945") (2.8945 - 2.8949")

     
 

R65, R65LS

81.995 - 82.005mm

82.005 - 82.015mm

82.015 - 82.025mm

 

(3.2281 - 3.2285") (3.2285 - 3.2289") (3.2289 - 3.2293")

     
 

R75/5, R75/6

82.000mm (3.2283")

82.010mm (3.2287")

82.020mm (3.2291")

 

R75/7

82.005 - 82.015mm (3.2285 - 3.2289")

82.015 - 82.025mm (3.2289 - 3.2293")

82.025 - 82.035mm (3.2293 - 3.2297")

 

All 800cc models

84.795 - 84.805mm (3.3384 - 3.3388")

84.805 - 84.815mm (3.3388 - 3.3392")

84.815 - 84.825mm (3.3392 - 3.3396")

 

R90/6, R90S

90.000mm (3.5433")

90.010mm (3.5437")

90.020mm (3.5441")

 

All 1000cc models

94.005 - 94.015mm (3.7010 - 3.7014")

94.015 - 94.025mm (3.7014 - 3.7018")

94.025 - 94.035mm (3.7018 - 3.7022")

 

Rebore sizes:

     
 

/5,/6, R60/7, R75/7 - 1st

0.50mm (0.020")

   
 

/5,/6, R60/7, R75/7 - 2nd

1.00mm (0.040")

   
 

R45 & R65 to '80, R80/7 - 1st

0.25mm (0.010")

   
 

R45 & R65 to '80, R80/7 - 2nd

0.50mm (0.020")

   
 

All 1000cc models to '80

0.25mm (0.010")

   
 

All models '81 on

rebores not possible, pistons and cylinders must be renewed when excessively worn

 

Maximum ovality:

     
 

R45, R65, R65LS

0.005mm (0.0002")

   
 

R80G/S, R80ST - 20mm (0.8") from top of bore

0.005mm (0.0002")

   
 

R80G/S, R80ST - 115mm (4.5") from top of bore

0.010mm (0.0004")

   
 

All other models

0.010mm (0.0004")

   
 

Maximum taper:

     
 

/5,/6

0.010mm (0.0004")

   
 

All other models

0.020mm (0.0008")

   

Pistons

 

Standard OD - at specified size code:

     
 

 

A

B

C
 

R50/5

66.960mm (2.6362")

66.970mm

(2.6366")

66.980mm

(2.6370")

 

R45

69.955 - 69.965mm (2.7541 - 2.7545")

69.965 - 69.975mm (2.7545 - 2.7549")

69.975 - 69.985mm (2.7549 - 2.7553")

 

R60/5, R60/6

73.460mm (2.8921")

73.470mm (2.8925")

73.480mm (2.8929")

 

R60/7

73.470mm (2.8925")

73.480mm (2.8929")

73.490mm (2.8933")

 

R65, R65LS

81.955 - 81.965mm (3.2266 - 3.2270")

81.965 - 81.975mm (3.2270 - 3.2274")

81.975 - 81.985mm (3.2274 - 3.2278")

 

R75/5, R75/6

81.960mm (3.2268")

81.970mm (3.2272")

81.980mm (3.2276")

 

R75/7

81.965mm (3.2270")

81.975mm (3.2274")

81.985mm (3.2278")

 

All 800cc models

84.765mm (3.3372")

84.775mm (3.3376")

84.785mm (3.3380")

 

R90/6, R90S

89.960mm (3.5417")

89.970mm (3.5421")

89.980mm (3.5425")

 

All 1000cc models

93.960mm (3.6992")

93.970mm (3.6996")

93.980mm (3.7000")

 

Standard piston/cylinder clearance:

 

/5,/6

0.035 - 0.045mm (0.0014 - 0.0018")

   
 

R60/7

0.020 - 0.040mm (0.0008 - 0.0016")

   
 

R75/7

0.019 - 0.041mm (0.0007 - 0.0016")

   
 

R80/7

0.023 - 0.047mm (0.0009 - 0.0029")

   
 

R45 & R65 up to '80

0.030 - 0.050mm (0.0012 - 0.0020")

   
 

All 1000cc models up to '80

0.028 - 0.052mm (0.0011 - 0.0021")

   
 

All models '81 on

0.030 - 0.040mm (0.0012 - 0.0016")

   
 

Maximum permissible piston/cylinder clearance:

 

/5,/6

0.120mm (0.0047")

   
 

All other models

0.080mm (0.0032")

   
 

Piston weight group

+ or - stamped in piston crown - both

   
 

Pistons must be of the same weight group, i.e. carry the same marking.

Piston rings

 

Top:

 

Type

Plain, rectangular section

   
 

Thickness:

 

/5,/6

1.790 - 1.810mm (0.705 - 0.0713")

   
 

R45

1.478 - 1.490mm (0.582 - 0.0587")

   
 

All other models

1.728 - 1.740mm (0.0680 - 0.0685")

   
 

End gap - installed:

 

R50, R60

0.25 - 0.40mm (0.0098 - 0.0158")

   
 

R45

0.25 - 0.45mm (0.0098 - 0.0177")

   
 

R75/5, R75/6, R90/6, R90S

0.30 - 0.45mm (0.0118 - 0.0177")

   
 

/7 '81 on

0.40 - 0.65mm (0.0158 - 0.0256")

   
 

All other models

0.30 - 0.50mm (0.0118 - 0.0197")

   
 

Side clearance:

 

/5,/6

0.060 - 0.070mm (0.0024 - 0.0028")

   
 

/7

0.060 - 0.090mm (0.0024 - 0.0035")

   
 

All other models

0.050 - 0.082mm (0.0020 - 0.0032")

   
 

Second:

 

Type

Plain, with stepped or tapered face

   
 

Thickness

 

/5,/6

2.030 - 2.050mm (0.0799 - 0.0807")

   
 

/7, R45 up to '80

2.010 - 2.022mm (0.0791 - 0.0796")

   
 

All other models

1.978 - 1.990mm (0.0779 - 0.0784")

   
 

End gap - installed:

 

R50, R60

0.25 - 0.40mm (0.0098 - 0.0158")

   
 

R45

0.25 - 0.45mm (0.0098 - 0.0177")

   
 

R80G/S, R80ST

0.30 - 0.50mm (0.0118 - 0.0197")

   
 

/7 '81 on

0.40 - 0.65mm (0.0158 - 0.0256")

   
 

All other models

0.30 - 0.45mm (0.0118 - 0.0177")

   
 

Side clearance:

 

/5,/6

0.050 - 0.060mm (0.0020 - 0.0024")

   
 

All other models

0.040 - 0.072mm (0.0016 - 0.0028")

   
 

Oil scraper:

 

Type

One piece

   
 

Thickness:

 

/5,/6

4.010 - 4.030mm (0.1579 - 0.1587")

   
 

/7

4.010 - 4.022mm (0.1579 - 0.1584")

   
 

R80G/S, R80ST, R45 '81 on

3.478 - 3.490mm (0.1369 - 0.1374")

   
 

R45 up to '80

3.510 - 3.522mm (0.1382 - 0.1387")

   
 

R65, R65LS

3.978 - 3.990mm (0.1566 - 0.1571")

   
 

End gap - installed:

     
 

R50/5, R60/5

0.20 - 0.35mm (0.0079 - 0.0138")

   
 

R60/6, R60/7

0.25 - 0.35mm (0.0098 - 0.0138")

   
 

R45

0.25 - 0.45mm (0.0098 - 0.0177")

   
 

All other models

0.25 - 0.40mm (0.0098 - 0.0158")

   
 

Side clearance:

 

/5,/6

0.030 - 0.040mm (0.0012 - 0.0016")

   
 

R60/7

0.020 - 0.050mm (0.0008 - 0.0020")

   
 

All other models

0.030 - 0.062mm (0.0012 - 0.0024")

   

Torque wrench settings

 

Component:

Nm

lb/ft

 
 

Rocker cover cap nut - R8, R80RT '85 on

20

15

 
 

Spark plugs

20 - 30

15 - 22

 
 

Valve adjuster locknuts

18 - 23

13.5 - 17

 
 

Cylinder head retaining nuts - all models up to '80:

 

1st stage

15

11

 
 

2nd stage

35

26

 
 

3rd stage

40

29.5

 
 

Standard setting

38 - 42

28 - 31

 
 

Cylinder head retaining nuts - all models '81 on:

 

1st stage

15

11

 
 

2nd stage

25

18.5

 
 

3rd stage

35

26

 
 

Standard setting

35 - 39

26 - 29

 
 

Exhaust pipe finned nuts:

 

R80, R80RT '85 on

160

118

 
 

R45 & R65 '79 - '80,/7 up to '80

140 - 180

103 - 133

 
 

All other models

200 - 220

148 - 162

 
 

Connecting rod bolts

48 - 52

35.5 - 38

 
 

Flywheel mounting bolts:

 

/5

58 - 62

43 - 46

 
 

R60/6 & R75/6 up to 9/74 - 10mm bolts

60 - 65

44 - 48

 
 

R90/6 & R90S up to 9/74 - 10mm bolts

70 - 75

52 - 55

 
 

/6 '75 on and all other models - 11mm bolts

100 - 105

74 - 77.5

 
 

Oil pump pickup mounting bolts

9

6.5

 
 

Camshaft flange bearing - all models '79 on

15 - 18

11 - 13.5

 
 

Sump mounting bolts

9 - 12

6.5 - 9

 
 

Alternator rotor retaining bolt

23 - 27

17 - 20

 
 

Starter motor mounting bolts

47.5

35

 
 

ATU retaining nut:

 

/5,/6

6 - 7

4.5 - 5

 
 

/7 up to '78

5 - 6

4 - 4.5

 
 

All other models

N/App

N/App

 
 

Oil filter inner cover retaining bolt - /5,/6 only

41

30

 
 

Engine oil drain plug:

 

Models up to '80

N/Av

N/Av

 
 

All models '81 on

41

30

 
 

Oil filter cover mounting bolts

10

7.5

 
 

Engine mounting nuts:

 

R80, R80RT '85 on

54.2

40

 
 

All other models

70 - 77

52 - 57

 


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