Wiring harness diagrams?

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Hi there! My dad and I have decided we are going to attempt to refit a new wiring harness to his 1972 750 Commando. He has had it down and torn apart for nearly 11 years, he tore it all down to have the frame powder coated, and to have all the body panels repainted, and just never got around to putting it all back together. All it really needs is the harness stuffed, and from there it would probably only take one day of work, consisting of putting simple mechanical stuff back on. So, I have found on ebay a color wiring diagram, problem is, it says its for a 1971 750, the seller doesnt seem to have a diagram for a 72 750, but he does have 1972-1974 850 commando diagrams. Anyone know if the 71 and 72 750's share the same wiring harness diagram? Or does anyone know of anyone that sells accurate and quality wiring diagrams? Thanks
 

L.A.B.

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72Fastback said:
seller doesnt seem to have a diagram for a 72 750, but he does have 1972-1974 850 commando diagrams.

The wiring diagrams cover model years, so if a diagram covers 1972 -1974 models then that should be suitable for all models '72-'74, after all there was no 850 model until 1973 so there cannot be a '72-'74 *850* diagram!

If you have a workshop manual then you should have these diagrams anyway?

And the factory manual shows a '72-'73 wiring diagram, the handlbar switches were swapped over at one point, although I'm not sure if there was any amended drawing that shows it?

The only real wiring difference on the later models ('73-'74) is a four position ignition switch that also controls the lighting circuit, there being some differences to the layout of the lighting circuit as a result, the rest of the wiring being practically identical.
 

Ron L

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If you are building a wiring harness from scratch, you can eliminate a lot of unnecessary wiring. The harnesses (and diagrams) have all the wiring for the Interpol model sirens and lights as well as turn signals for models not so equipped. If you have added an electronic ignition, there are now unnecessary wires here as well.

As I have said in the past, I am a big proponent of relays for lights, horn, and ignition to assure full voltage at these devices. This changes the wiring scheme also.
 

L.A.B.

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I believe I need to update what I said previously, as I wrote:
The only real wiring difference on the later models ('73-'74) is a four position ignition switch that also controls the lighting circuit, there being some differences to the layout of the lighting circuit as a result, the rest of the wiring being practically identical.

Actually I should have said '72-'74 models, not '73-'74, the four position switch was also fitted to '71 models (according to Roy Bacon's Norton Twin Restoration book) although the 1971 model wiring diagram would seem to show that the main switch did not originally make use of all of the switch positions, unlike the later models, and the headlamp wiring layout changed slightly as a result, from 1972-on.

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Addition

After doing a bit more research and according to the NOC Service Notes the '4 terminal master switch' replaced the 39565 switch at engine number 202116, and cross-referencing that number gives a production date for that change-over as January 1972. So the Roy Bacon info could be wrong? Or is the 39565 switch definitely a 'four position switch' but with only three terminals?? The original parts lists giving a different set of numbers, none of which are 39565.
 
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