Norton Commando Workshop Manual

## Engine/Primary Transmission

# C

| standing on the bench and a hammer driving a lump of soft wood against the crankcase facing, permitting this to be jarred free of the crankshaft. If removal should prove difficult by this means, the crankcase in the area surrounding the main bearing should be heated by a soft flame and the same removal procedure followed so that the main bearing and crankshaft together are displaced from the crankcase. The bearing can then be removed at a later stage. On engines after number 200000 a roller timing side bearing is used and on such units there should be no difficulty in crankshaft removal.

### SECTION C17

### CRANKCASE OVERHAUL

The following text covers the renewal of main bearings only. In our experience the camshaft bushes have an extremely long life and renewal cannot be accomplished without extensive machining facilities. To remove the main bearings, it is necessary to heat the area surrounding each main bearing with a soft flame such as a gasolene or kerosene (petrol or paraffin) blow lamp or butane or propane. Once the cases have been heated, in the case of a timing side crankcase equipped with the ball type of main bearing, use a suitable soft drift against the inner race of the main bearing and the bearing can be drifted out. In the case of a timing side crankcase equipped with the roller type of main bearing, heat the area of the crankcase surrounding the main bearing and by bumping the joint facing of the cankcase hard against a flat wooden surface, the main bearing outer race should be dislodged. In the case of drive side crankcases, the complete crankcase will need to be appreciably hotter since the only method of removing the main bearing outer race will be to bump the crankcase sharply against a flat wooden surface.
To refit the main bearings, the cases must be similarly heated and the main bearings, whether of the ball or roller variety should drop, completely freely, into their housings. The main bearings must be fully home into the housings both at the drive side and timing side cases.

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