Norton Commando Workshop Manual

## Technical Data

# A

### GEARBOX

| Ball journal bearings:
|  | Mainshaft (Clutch end) Ball journal 1 1/4 in. x 2 1/2 in. x 5/8 in. Mainshaft (K/S end): Ball journal 5/8 in. x 9/16 x 7/16 in. Layshaft (Clutch end): Ball journal 17 mm x 40 mm x 12 mm
| Reductions
|  | 4th (HIGH): 1:1 3rd: 1.21 :1 2nd: 1.70 :1 1st (LOW): 2.56:1
| Theoretical road speeds using various countershaft (gearbox) sprockets
|  | Table assumes standard sprockets: | Engine 26T
|  | Clutch 57T
|  | Rear 42T

Engine RPM | Sprocket Teeth | 19 | 20 | 21 | 22 | 23
Overall Gear Ratio | 4.84 | 4.60 | 4.38 | 4.18 | 3.99
6000 | 92 | 97 | 102 | 106 | 112
6500 | 99 | 105 | 110 | 115 | 121
7000 | 107 | 113 | 119 | 124 | 130

| Overall Ratios | With 19T Gearbox | With 21T Gearbox |
|  | Sprocket | Sprocket |
|  | 4th (HIGH): | 4.84:1 | 4.38:1 |
|  | 3rd: | 5.90:1 | 5.30:1 |
|  | 2nd: | 8.25:1 | 7.45:1 |
|  | 1st (Low): | 12.40:1 | 11.20:1 |
| No. of tecth on pinions

Layshaft: 4th 14t
Layshaft: 3rd 20t
Layshaft: 2nd 24t
Layshaft: 1st 28t
Mainshaft: 4th 23t
Mainshaft: 3rd 21t
Mainshaft: 2nd 18t
Mainshaft: 1st 14t

| Gearbox

High gear bush O.D.: 0.9060/0.9053 in. (23.012/22.995 mm)
High gear bush l.D.: 0.8145/0.8140 in. (20.688/20.675 mm)
High gear bush fitted l.D.: 0.8133/ .8120 in. (20.657/20.625 mm)
Layshaft bush l.D.: 1.126 in./1.124 in. (28.60/28.549 mm)
Mainshaft second gear bush fitted l.D.: 0.8125/0.8115 in. (20.637/20.608 mm)
Layshaft third gear bush fitted l.D.: 0.8125/0.81 in. (20.637/20.57 mm)
Layshaft first gear bush fittod l.D.: 0.6885/0.6875 in. (17.488/17.462 mm)
Footchange spindie bush, K/S case fitted l.D.: 0.6290/0.6285 in. (15.976/15.964 mm)
Camplate/Quadrant bush fitted l.D.: 0.5005/0.4995 in. (12.713/12.687 mm)
K/S spindie bush fitted l.D.: 0.675/0.673 in. (17.145/17.094 mm)
Gearbox sprocket: 19T Standard

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