Norton Commando Workshop Manual

## Gearbox

# D

### SECTION D1

### GEARBOX DESCRIPTION

The transmission (gearbox) is a self contained 4 speed unit, completely separate from the engine crankcase and thus simple and inexpensive for servicing. A robust aluminium alloy casing with separate inner and outer covers contains a gear cluster of extra tough nickel chrome steel. Selection is foot controlled through a positive stop mechanism to a rotating cam plate. Hardened steel selector forks operated by the camplate position the gear pinions.
The kickstart drives through an internal ratchet on the layshaft first gear which in turn drives the mainshaft and clutch.

### SECTION D2

### GEARBOX DISMANTLING

It is not necessary to remove the exhaust system whilst giving attention to the gearbox, providing the gearbox is not to be removed from the engine plates.

### SECTION D3

### REMOVING GEARBOX OUTER COVER

Prior to gearbox dismantling it is recommended that the gearbox shouid be drained into a suitable sized drain tray using the drain plug at the bottom rear of the gearbox casing. Proceed then as follows:
1 | Remove the kickstart by releasing the single securing bolt. The bolt locates into a groove in the kickstart spindle and thus it is necessary to remove this bolt completely.
2 | If the battery is still connected, disconnect by removing the fuse before proceeding to the next operation.
3 | Remove the two nuts and one bolt securing the right hand footrest and note that the bolt also secures the red earth lead tag from behind the footrest mounting plate. A nut without washer is used on the footrest securing bolt. It is vitally important during re-assembly not to overlook the refitting of this earth lead or otherwise a short circuit may result in the fuse being blown, or damage to the Zener diode.

4 | Remove the gear indicator pointer from the gear shift spindle. This is secured by a set screw and plain washer.
5 | Release the clamping bolt from the gear shift lever and slide the lever off the splines.
6 | Remove the five cheese headed set screws from the gearbox outer cover.
7 | Remove the two screws securing the outer cover inspection cap which may then be lifted away complete with gasket.
8 | Disconnect the clutch cable from the fork within the gearbox outer cover.
9 | With the oil drain tray again in position beneath the gearbox, work loose and withdraw the outer cover.
10 | Withdraw the ratchet plate and spindle.

### SECTION D4

### REMOVING GEARBOX INNER COVER

Prior to removing the gearbox inner cover it is necessary to mark clearly the position of the clutch operating body by two punch marks which are shown in Fig. D1. This is due to the fact that the clutch operating body has no positive rotational location. Proceed as follows:
1 | Remove the small lever, screw and nut securing the clutch operating arm and collect the arm, roller and bush.
2 | Remove the clutch operating body locking ring as in Fig. D1 and lift away the clutch operating body and the ball.

<< | < | rocbo.net | >