Norton Commando Workshop Manual

## Gearbox

# D

3 | Prevent the gearbox from turning by engaging top gear as follows and applying the back brake fully. Top gear can be engaged by levering the end of the quadrant carefully to the top of the window in the gearbox inner cover whilst rocking the rear wheel. At this stage the mainshaft nut can be removed.
4 | In order to remove the gearbox inner cover it will be found simpler to revert to the neutral position, again by moving the end of the quadrant down the window.
5 | Remove the seven securing nuts to the gearbox inner cover. These nuts are all of equal size, five within the case and two outside.
6 | Remove the gearbox inner cover, if necessary tapping the end of the mainshaft to ease separation. The inner cover should then be lifted away, complete with kickstart spindle, with the paw assembled and also the return spring.

### SECTION D5

### DISMANTLING GEAR CLUSTER AND CAMPLATE

To dismantle the gearbox further it is necessary to remove the clutch from the gearbox mainshaft and if the sleeve gear is to be removed from the gearbox, the countershaft sprocket must also be removed. Clutch removal is covered in items 1 to 9 of Section C13 and C14 and countershaft sprocket removal in Section D8.
4 | Remove the clutch location shims (if fitted) and the clutch locating spacer.
5 | Remove low gear pinion from mainshaft.
6 | Unscrew selector fork spindle and remove.
7 | Slip out selector forks, remove clutch rod, and withdraw mainshaft with gears.
8 | Remove layshaft with gears.
9 | Remove countershaft sprocket as in Section D8.
10 | Remove the mainshaft sleeve gear. The sleeve gear is a tight push fit into the bearing and may need to be dislodged by careful use of a hide mallet, tapping the sleeve gear back through the bearing into the gearbox.

11 | Remove the acorn-shaped plunger spring bolt from beneath the front of the gearbox shell. As this is removed, it will release also the camplate plunger
12 | Remove the two bolts and washers securing the camplate and quadrant to the gearbox shell.
13 | Lift out the camplate and quadrant from the shell, and collect the 'O' rings.

### SECTION D6

### INSPECTION OF GEARBOX PARTS

After cleaning all components very thoroughly such as in gasoline (petrol) or kerosene (paraffin) check all items thoroughly as below:
1 | Inspect the two mainshaft and one layshaft ball journal bearings for roughness indicating ball or ball track damage on either the inner or outer races. Feel for side play between the inner and outer races. If the bearings are in good condition, such play should be negligible.
2 | Inspect both the layshaft and mainshaft for wear on the splines, damage to the threads, out of truth and severe wear and grooving on the bearing diameters.
3 | Inspect all pinions for chipping or obvious wear to the teeth. Ensure that the dogs are not badly rounded and that the inner splines are a satisfactory fit to the shafts. Bushed pinions should be offered to the shafts and checked for excessive wear by attempting to rock them on the shafts.
4 | Inspect the gearbox shell and gearbox inner cover bushes for obvious wear. Note that wear on the bushes in the shell supporting the camplate and quadrant can result in bad gear indexing and a tendency to jump out of gear engagement.
5 | Inspect the selector forks and mating grooves in the sliding pinions for seizure or wear.
6 | Especially in cases of bad selection, inspect the camplate tracks for wear or distortion and ensure that the camplate spindle is a good fit in the bush in the gearbox shell.

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