Denco Porting Specs
(Complete)
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Denco Porting Specifications-all measurements in millimeters |
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Exhaust |
Boost |
Transfer |
Intake |
Piston Skirt |
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H2 |
74 (Stock) |
36.8 X 43.0 |
51.7 |
51.7 |
66.1 X 48.5 |
Stock |
|
H2 |
Ultra Stock |
36.8 X 43.0 |
51.7 |
51.7 |
95.9 |
6.0 |
|
H2 |
100 |
33.6 X 65% of bore |
50.9 X 20.0 |
Stock |
Stock |
4.0 |
|
H2 |
120 |
32.6 X 65% of bore |
49.3 X 23.0 |
50.9 |
Stock |
5.22 |
|
H2 |
120 (King Cobra) |
32.6 X 48.0 |
49.9 X 23.0 |
50.9 |
Stock |
5.22 |
|
H2 |
130 (Production Road Race) |
32.2 X 49.0 |
49.9 X 24.0 |
50.9 |
Stock |
5.22 |
|
H2 |
141 |
31.5 X 49.0 |
49.6 X 24.0 |
50.9 |
Stock |
6.1 |
|
H2 |
149 |
31.0 X 48.0 |
49.6 X 25.0 |
49.6/51.7 |
97.9 X Stock |
4.8 |
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H1 |
60 (Stock) |
35.4 X 39.0 |
48.8 |
48.8 |
65.4 X 41.0 |
Stock |
|
H1 |
70 |
33.8 X Stock |
Stock |
Stock |
Stock |
2.0 |
|
H1 |
75 (Road Race) |
33.4 X Stock |
Stock |
Stock |
Stock |
1.8 |
|
H1 |
80 |
32.0 X 70% |
47.0 |
47.9 |
Stock |
2.25 |
|
H1 |
90 |
31.5 X 70% |
47.0 |
47.9 |
Stock |
2.25 |
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| S3 | 42 (Stock) | 33.0 X 36 | 44.0 | 44.0 | 55.5 X 36.0 | Stock |
|
S3 |
62 |
29.5 X Stock |
Stock |
Stock |
Stock |
2.1 |
|
S3 |
66 (Road Race) |
28.3 X 38.75 |
42.1 |
42.8 |
Stock |
3.6 |
|
S3 |
72 |
28.0 X 38.75 |
42.1 |
43.0 |
Stock |
3.8 |
|
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| S2 | 45 (Stock) | 31.0 X 35.5 | 33.5 | 33.5 | 59.0 X 36.0 | Stock |
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S2 |
60 |
28.3 X 65% |
42.1 |
42.8 |
Stock |
5.4 |
- All intake and exhaust cut 70mm radius.
- 100HP and above must have heads milled about 0.020” and work your way up 0.010” at a time to attain 155 psi. This is required to compensate for raising exhaust port.
- Run only 120-130 psi for road racing.
- All Denco heads are of the dual squish design.
- Outside air temp where you are riding can have an effect. Where it is cold you can get by with higher compression. If it is hot you want to keep compression low. You may want to have two sets of heads.
- Higher HP versions used larger carbs, ie, 149HP version used 38mm carbs.