HONDA CR750
Joep Kortekaas' Honda 750 CR kitted race bike
Engine Analysis
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Motor Power Inlet System Exhaust System Friction and Drag
Restoration Process Photo Gallery Joep Koortekaas Page
0 |
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F = A.Cv.r/2g.(0.0772).v² |
[kg] |
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P = A.Cv.r/2g.(0.0214).v³ |
[hp] |
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g is gravitational acceleration in m/s2 |
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v is speed in km/h, 0.072 and 0.0214 are factors to go from m/s to km/h. |
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Frontal area A |
0.52 |
m² |
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Shape factor Cv |
0.46 |
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Specific density air r |
1.2 |
kg/m³ |
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Weight, bike plus rider |
230 |
kg |
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Friction coefficient f |
0.015 |
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Mechanical efficiency crankshaft - rear wheel is taken as 85% |
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Primary reduction I1 |
0.588 |
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Final drive ratio lf |
0.857 |
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Gear ratios |
Primary reduction x gear ratio x final drive ratio |
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1st gear |
0.585 |
0.295 |
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2nd gear |
0.71 |
0.358 |
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3rd gear |
0.833 |
0.420 |
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4th gear |
0.94 |
0.474 |
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5th gear |
1.1 |
0.554 |
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| Secosecondary reduction ratio I2 | |||||||
17/44 |
0.386 |
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17/45 |
0.378 |
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17/46 |
0.370 |
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17/47 |
0.362 |
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17/48 |
0.354 |
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17/49 |
0.347 |
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18/44 |
0.409 |
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18/45 |
0.400 |
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18/46 |
0.391 |
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18/47 |
0.383 |
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18/48 |
0.375 |
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18/49 |
0.367 |
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Rear tyre diameter |
18 |
" |
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Rear tyre width |
3.50 |
" |
Rear wheel circumference (dyn.) |
2.04 |
m |
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Radius rear wheel (dynamic) 11) |
0.325 |
m |
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11) For dynamic growth of the tyre, 2.5% of the diameter has been choosen. |
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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 |
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Motor Power Inlet System Exhaust System Friction and Drag
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Copyright: Murray Barnard/Joep Kortekaas - 1999