HONDA CR750

Joep Kortekaas' Honda 750 CR kitted race bike

Engine Analysis

Warning: (this is quite a graphic and table intensive page to load,; but worth the wait)

Motor    Power    Inlet System    Exhaust System     Friction and Drag

Restoration Process     Photo Gallery    Joep Koortekaas Page

 

FRICTION AND DRAG

0

F = A.Cv.r/2g.(0.0772).v

[kg]

P = A.Cv.r/2g.(0.0214).v

[hp]

g is gravitational acceleration in m/s2

v is speed in km/h, 0.072 and 0.0214 are factors to go from m/s to km/h.

Frontal area A

0.52

m

Shape factor Cv

0.46

Specific density air r

1.2

kg/m

Weight, bike plus rider

230

kg

Friction coefficient f

0.015

Mechanical efficiency crankshaft - rear wheel is taken as 85%

Primary reduction I1

0.588

Final drive ratio lf

0.857

Gear ratios

Primary reduction x gear ratio x final drive ratio

1st gear

0.585

0.295

2nd gear

0.71

0.358

3rd gear

0.833

0.420

4th gear

0.94

0.474

5th gear

1.1

0.554

Secosecondary reduction ratio I2

17/44

0.386

17/45

0.378

17/46

0.370

17/47

0.362

17/48

0.354

17/49

0.347

18/44

0.409

18/45

0.400

18/46

0.391

18/47

0.383

18/48

0.375

18/49

0.367

Rear tyre diameter

18

"

Rear tyre width

3.50

"

Rear wheel circumference (dyn.)

2.04

m

Radius rear wheel (dynamic) 11)

0.325

m

11) For dynamic growth of the tyre, 2.5% of the diameter has been choosen.

wpe11.jpg (40170 bytes)

 

Speed

Force [kg]

Force [kg]

Force

Power

Power

Power

[km/h]

friction

drag

total

friction

drag

total

0

3.5

0.0

3.5

0.0

0.0

0.0

0

10

3.5

0.1

3.6

0.1

0.0

0.1

10

20

3.5

0.5

3.9

0.3

0.0

0.3

20

30

3.5

1.0

4.5

0.4

0.1

0.5

30

40

3.5

1.8

5.3

0.5

0.3

0.8

40

50

3.5

2.8

6.3

0.6

0.5

1.2

50

60

3.5

4.1

7.5

0.8

0.9

1.7

60

70

3.5

5.5

9.0

0.9

1.4

2.3

70

80

3.5

7.2

10.7

1.0

2.1

3.2

80

90

3.5

9.1

12.6

1.1

3.0

4.2

90

100

3.5

11.3

14.7

1.3

4.2

5.4

100

110

3.5

13.7

17.1

1.4

5.6

7.0

110

120

3.5

16.3

19.7

1.5

7.2

8.7

120

130

3.5

19.1

22.5

1.7

9.2

10.8

130

140

3.5

22.1

25.6

1.8

11.4

13.2

140

150

3.5

25.4

28.9

1.9

14.1

16.0

150

160

3.5

28.9

32.4

2.0

17.1

19.1

160

170

3.5

32.6

36.1

2.2

20.5

22.7

170

180

3.5

36.6

40.0

2.3

24.3

26.6

180

190

3.5

40.8

44.2

2.4

28.6

31.0

190

200

3.5

45.2

48.6

2.5

33.4

35.9

200

210

3.5

49.8

53.3

2.7

38.6

41.3

210

220

3.5

54.7

58.1

2.8

44.4

47.2

220

230

3.5

59.7

63.2

2.9

50.8

53.7

230

240

3.5

65.1

68.5

3.1

57.7

60.7

240

250

3.5

70.6

74.0

3.2

65.2

68.4

250

260

3.5

76.3

79.8

3.3

73.3

76.6

260

270

3.5

82.3

85.8

3.4

82.1

85.5

270

280

3.5

88.5

92.0

3.6

91.6

95.1

280

290

3.5

95.0

98.4

3.7

101.7

105.4

290

Required total power to overcome friction and drag

Motor    Power    Inlet System    Exhaust System     Friction and Drag

Restoration Process

Photo Gallery

Joep Koortekaas Page

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Copyright: Murray Barnard/Joep Kortekaas - 1999