Mk 3 wiring

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A friend of mine (and club member) has recently bought a part finished Mk3 commando project, he's got most of the bike assembled but is having difficulties sorting out the wiring, which is about all thats left to do. It has a new loom already fitted but he is having difficulty working out which bits go where, how they connect and what connectors it should have. Is there anyone in Devon ( Hes near Dawlish) that either anyone can recommend he can take the bike to, or better still a Commando savy member that would be prepared to give him a hand and at least point him in the right direction!
Cheers
Dan

Start with the wiring diagram...

The wiring diagram will have all the correct colours which should tie up with the loom hence connecting up will be straight forward. If you have moved any electrical items or changed any items then there is scope for confusion.
If the ignition system is changed to Electronic (which it should be) then condensers and ballast resistors are no longer needed.
If the Zener diodes are lost or considered unusable then the 'odd' original rectifier fitted to the MKIII and Zeners will be replaced by a regulator/rectifier.
IF the new loom isn't in line with the wiring diagram then of course the new loom is 'not fit for purpose'.

Enter Mk3 final wiring into…

Enter Mk3 final wiring into the search box above.

Regards, Al.

Sorry for the delay replying…

Sorry for the delay replying - thanks for your reply Al, ill see what i can do to help and come back with any specific questions.
Dan

f there is anything non…

f there is anything non-standard about the electrical set-up, it is very possible that Grant Tiller has a modified wiring diagram for it: https://granttiller.com/

Julian, Thanks thats a…

Julian, Thanks thats a useful resource.

Am I right in thinking that the headlight, ignition switch and warning light cluster have separate sub looms?

I think that/they are missing which isn't helping!

Dan

Hi, It is clear from the…

Hi, It is clear from the circuit diagram that the headlight, ignition switch and warning light cluster do have separate sub looms. (Note:- Ignore anything in the area of the alternator in the attached, it was part way through me redrawing the diagram for the way my bike is)

Ok my friend .....honestly -…

Ok my friend .....honestly - I dont own a commando! Is still struggling with the wiring of his 850 electric start. It's bunch to me shortly as another friend of his was unable to solve the riddle!

Simple question first, the wiring looms (fitted by the previous owner but not connected) seem to have a coloured thread running through them, the rear secton is black with a yellow thread, the middle bit black with a blue thread and the front section is black and yellow again. Is this of any significance? The problem seems to be with the black and blue section which has a bunch of white block connectors that don't seem to have an obvious home. But can he find anyone selling the reciprocal white connectors anywhere. I'll know more when I get the bike, but am I missing something simple here?!

Hi Dan, Have a look at (for…

Hi Dan,

Have a look at (for example)
https://www.feked.com/genuine-lucas-main-wiring-harness-norton-commando-mk3-06-6396.html?srsltid=AfmBOopPU-xEJZwqWeQgnwnRrlcfb5ataplt7BIaURz38kD1DYOBbR7M
And you will see a picture of the main harness with yellow thread.
and
https://www.feked.com/genuine-lucas-headlamp-wiring-harness-norton-commando-mk3-1975-06-6438.html
For a picture of the headlamp harness.
The colours of the wires will be as per the circuit diagram.
Other sub harnesses are available but you get the idea.
You should be able to look at wire colours and tie them up with the circuit diagram.
By the way, I have never found anywhere where you can buy the white connectors. Obviously they are available as the looms have them. Anyone know of a supplier?

Thanks,Ive just received the…

Thanks,Ive just received the bike and will post some pictures soon. I think part of the problem is that the main harness has another harness connected but is not right, (the blue threaded one) I also have a headlight and ignition harness that does seem to be right!

I was just looking through the Access Norton site and found this link for connectors https://tricor-andy.com/product/4-pin-connector/. They do others!

Dan

No wonder it was confusing …

No wonder it was confusing .... there were two headlight harnesses connected to each other`!! having removed the offending item I have now been able to identify all the major wires, my only questions now are of a more practical nature, there are 3 wires coming from the stator but only 2 connectors on the Lucas loom, if I've understood it correctly, I'm assuming its a three phase and will need to work out how to connect it to a regulator rectifier - but its progess - any advice greatly received, I'm more familiar with 1950's dynamo singles!
Dan

3 Phase (or not)

Firstly ascertain if you have a 3 phase stator? Does it have 9 pole pieces? (6 poles pieces is single phase)
The original MKIII system will have 3 wire connections to the two alternator connections, ie the original rectifier, the two Zeners on the AC side of the rectifier and the 2 to the Ignition Warning Light unit. (4 connections in total)
I suggest these 2 off triple wires are 'removed' or 'made safe' and not used.
Install 3 off new wires (YLW) from your new stator to the regulator rectifier. And redirect the Ignition Warning Light unit to two of these stator wires. Unless you are cancelling that system and fitting a BSM, which works on the DC side of things.

Sourcing White Connectors

Att'n Tony Ripley

Tony, are you able to confirm whether these Tricour connectors that Dan mentions are indeed the correct ones?

Or can anyone else for that matter? Anyone used them, and are they well made?

Cheers.

James, The replacement block…

James,

The replacement block connectors aren`t great, they are small and tricky to connect pins to wires. I would recommend removing them and using original type bullets or modern equivalent which will also cause less space issues under the tank.
The blue and yellow flecking on the harness sleeving has no significance I believe, presumably they are manufactured by two different companies, even if supplied by the same distributor (Wassell) who don`t seem to be able to get the original specification right ie plastic sleeving.
I have incorporated the earlier warning lights into a Mk3 console and fitted a BMS in the ignition light housing as you mention but it`s hard to see with the red lens so a clear lens is needed if anyone knows of a source?

Regards, Al H

Hi James, They certainly…

Hi James,
They certainly look the same but I have never bought any.
As to are they well made, they look just as well made as the original ones, take that any way you wish. I have replaced the lot on my bike.
Tony

Hi Al, I haven't had a look…

Hi Al, I haven't had a look at the stator yet, the cover is on and I'm away at the moment, I will have a look when I get back. But thank you for the advice. Im not sure what Kerry wants to do about the charge light but I would probably suggest a BSM. I'll report back when I know some more.

James, Ive ordered some connectors - Ill keep you posted!

Dan

Warning Lamps

Cheers Dan,and love the bike! Is that a side panel from an Indian Velocette that I can see?

It's a great shame that the BSM warning light lens doesn't match a much needed upgrade to the factory MK3 warning lamps on the console (which are fragile and a pain). I guess they were originally relatively cheap in '74, and my, don't they look it when removed.

I understand that the earlier Commando headlight shell warning lenses can be easily substituted, and I'm wondering if the BSM charging light lens could be reliably incorporated into a transparent earlier lens, in the space currently occupied by the assimilator lamp?

James - it's a Rickman…

James - it's a Rickman Metisse with a shortstroke 500 engine, built by Mike Pemberton - I race it at Classic scrambles, it's looks get more appreciation than my racing skills! It's great fun to ride!

Dan

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