Clock Holder?Parts manuals and parts

First of all, I am Chucks wife and can anyone tell me what the clock holder is? Secondly, we believe we have a 73 Norton. Bought the parts manual #06-5034. Bike could be a 72. Parts manual for that is 06-3402. Can anyone tell me the big difference in these manuals. Also need to know where the most reasonable place is to obtain NOS parts or factory type parts.
Thanks,Fran

Clock Holder

Hi Chuck's wife, Fran,

The clock holder is the aluminum alloy canister that the speedometer and tachometer fit into. This is then attached to the top of the fork leg by the top fork cap. The '72 used a shorter natural finish holder, while the '73 used an extended version that was painted matt black (same as used on the 850 Commando). There are available some soft plastic covers that go over the extension at the bottom to keep out dust...etc, a nice feature.

The best way to distiquish a '73 750 Commando from a '72 is the engine number. '73 started with 220xxx. I've owned both years, current have a '72 combat roadster.

Parts are readily available from several sources. By mail order I've used Norvil Motorcycles in England www.norvilmotorcycle.co.uk
The parts book for the two years would be the same.