* Reverse and 2 speed sprocket
Chain case performance specifications
sprockets ratio chain pitch MPH=0.0192 x RPM x ratio MPR/RPM (engine)
6000 7000 8000 9000 10,000
24/35
.686
70
79.0
92.2
105.4
118.5
131.7
22/33
.667
68
76.8
89.6
102.5
115.3
128.1
21/33
.636
68
73.3
85.5
97.7
109.9
122.1
24/39
.615
72
70.8
82.7
94.5
106.3
118.1
22/37
.595
70
68.5
80.8
91.4
102.8
114.2
23/40
.575
72
66.2
77.3
88.3
99.4
110.4
20/35
.571
68
65.8
76.7
87.7
98.7
109.6
21/37
.568
70
65.4
76.3
87.2
98.2
109.1
22/40
.550
72
63.3
73.9
84.5
95.0
105.6
19/35
.543
68
62.6
73.0
83.4
93.8
104.3
22/41
.536
72
61.7
72.0
82.3
92.6
102.9
20/39
.513
70
59.1
68.9
78.8
88.6
98.5
21/41
.512
72
59.0
68.8
78.6
88.4
98.3
21/42
.500
72
57.6
67.2
76.8
86.4
96.0
20/41
.488
72
56.2
65.6
75.0
84.3
93.7
19/39
.487
70
56.1
65.5
74.8
84.2
93.5
18/37
.486
68
56.0
65.3
74.6
84.0
93.3
16/33
.484
66
55.8
65.0
74.3
83.6
92.9
19/40
.475
70
54.0
63.0
72.0
81.2
90.0
20/43
.465
72
53.6
62.5
71.42
80.4
89.3
19/41
.463
72
53.3
62.2
71.1
80.0
88.9
18/39
.461
70
53.2
62.1
71.0
79.8
88.7
17/37
.459
68
52.9
61.7
70.5
79.3
88.1
18/40
.450
70
51.8
60.4
69.1
77.8
86.4
19/43
.442
72
50.9
59.4
67.89
76.4
84.9

bold lettering indicates perfect chain fit.
*use as a guide only

When using 9 tooth drives, multiply above chart to compensate for overdrive clutch and longer drives. example: 20/39 at 8000 rpm using data from above chart of 78.8 mph x 1.24 = 97.71 mph. when using 10 tooth drivers, multiply above chart by 1.36 to compensate for overdirve and extra large drivers. example: 20/39 at 8000 rpm using data from above chart of 78.8 mph x 1.36= 107.17 mph.