Wiring Advice Please?

Hi there,

I am about to remove the wiring from my Mk2 model. In the pictures below does the wiring and particularly the bunches of connectors taped together look typical of the wiring loom on the Commando?









What is the accepted standard when restoring a Commando's wiring?

Repair the wiring?
Remove connectors and replace with soldered joints?
Replace the wiring loom with new and if so which loom is best and where to get it from?

Is it normal to have that big bunch of connectors taped together in front of the top engine mount?

Any suggestions and help offered will be REALLY appreciated.

Thanks

Don

Yeah, that looks like a typical wiring loom. The replacement harnesses are available in either taped or cloth-wrapped. Take lots of pictures of the old harness as you remove it - they'll help in the replacement.

The main loom contains the bulk of the wiring for the bike, but not all of it. The grey-sheathed wiring for each handlebar switch assembly is separate, as is the wiring inside the headlight and the small bundle that goes to the rear tail light/turn signal assembly.

My '73 basket case had a chopped main harness, so I got a new cloth-covered harness. The colors in the replacement looms are a good match to the original, so if you can read a wiring schematic, you got a fairly easy time of it.

If the original loom is in decent shape, you may be better off just going through it and cleaning it up. If you've got wiring problems, the likely cause is those Lucas bullet couplers. The same companies that sell replacement harnesses also sell replacement connectors in most of the configurations found on a Commando.

Thanks Bill,

Do the two grey sheathed wiring from handlebar switches plug into the main harness where the bulk of connectors are located under the fuel tank? I guess the coils feed from there as well do they? Where does the wiring from the headlight connect to? Yes I am ok on reading wiring diagrams and can do all the practical tasks like soldering, crimping, etc and possess all the crimping and stripping tools that will be required.

Which supplier is best if I do need a new harness?

Thanks

Don

thunderbolt said:

I am about to remove the wiring from my Mk2 model. In the pictures below does the wiring and particularly the bunches of connectors taped together look typical of the wiring loom on the Commando?

Click to expand...

If you mean the basic layout, then yes but not all the tape and general condition of it.

thunderbolt said:

What is the accepted standard when restoring a Commando's wiring?

Click to expand...

Your bike, what would you consider to be acceptable?

thunderbolt said:

Repair the wiring?

Click to expand...

Either replace with new harness sections or make your own if you consider yourself able to do so.

thunderbolt said:

Remove connectors and replace with soldered joints?

Click to expand...

No, but replace all the old female bullet connectors.

thunderbolt said:

Replace the wiring loom with new and if so which loom is best and where to get it from?

Click to expand...

For you, probably British Wiring: http://www.britishwiring.com/Norton-s/23.htm
Or Andover Norton: https://andover-norton.co.uk/en/shop-drawings/6
https://andover-norton.co.uk/en/distributors/

thunderbolt said:

Is it normal to have that big bunch of connectors taped together in front of the top engine mount?

Click to expand...

There would normally be a large rubber multiway connector: http://www.britishwiring.com/C-336-p/c336.htm and perhaps a few singles and doubles but not taped and tied up like that.

thunderbolt said:

Do the two grey sheathed wiring from handlebar switches plug into the main harness where the bulk of connectors are located under the fuel tank?

Click to expand...

Yes.

thunderbolt said:

I guess the coils feed from there as well do they?

Click to expand...

Yes, but you need to take into consideration the type of ignition (electronic or points) that you will be using.

thunderbolt said:

Where does the wiring from the headlight connect to?

Click to expand...

A separate harness section runs forward to the headlamp from that main junction area below the fuel tank.

since you will be connecting new wires to old stuff like coil terminals, headlight switch terminals, key switch terminals and old bullet terminals, there is some great stuff from the electronics industry called DE-OXIT 5 , spray stuff that really works and promotes good contact on old bits by actually dissolving old corrosion. it is especially good to get inside old female spade and bullet connectors where it is impossible to reach with a file or sandpaper. And don't forget to scuff up ALL your old grounds.

Rather than scrape the paint of your frame or any metal part of the bike, I suggest you run decent earth wires to every electronic part of the bike.

Years ago a guy I knew restored an old 30's Indian. It was beautifull. But his lights would not work , so he scraped the paint of his guards etc to get an earth. What a waste.

Dereck

When I first got my commando I noticed that the black big lump where all the wires are connected was pretty funky looking so I tried to get a replacement from Norvil but the woman who took my order said they didn't sell them anymore, and the reason was something about a potential fire hazard.

I broke mine into separate connections but I believe the block or something similar was used on a Jag and was available from British Wiring. That was quite awhile ago but if you have the lump and need to replace it you might want to check.

Dave

Hi LAB,

Thanks for going to the bother of the individual replies. That is appreciated.

One more question, when the connectors are all plugged together under the tank, how was the wiring harness held in position? Cable ties, other protection from frame and other bits?

Don

kerinorton said:

Rather than scrape the paint of your frame or any metal part of the bike, I suggest you run decent earth wires to every electronic part of the bike.

Years ago a guy I knew restored an old 30's Indian. It was beautifull. But his lights would not work , so he scraped the paint of his guards etc to get an earth. What a waste.

Dereck

Click to expand...

I know what you mean. On the last bike I restored I ran a 15amp earth wire from the headlight all the way to the tail light and tapped off it to connect earths to the frame, engine and all other parts that required an earth, indicators, lights, etc.

What a lot of people don't realise is that the earth wire carries the same current as the live/active wiring on the bike - that's why often the earth wire has the insulation melted as well when there is excessive current draw.

Thanks for your comments. appreciated.

Don

seattle##gs said:

since you will be connecting new wires to old stuff like coil terminals, headlight switch terminals, key switch terminals and old bullet terminals, there is some great stuff from the electronics industry called DE-OXIT 5 , spray stuff that really works and promotes good contact on old bits by actually dissolving old corrosion. it is especially good to get inside old female spade and bullet connectors where it is impossible to reach with a file or sandpaper. And don't forget to scuff up ALL your old grounds.

Click to expand...

Thanks Seattle GS, I will look around for some. Sounds like a GOOD idea.

Cheers
Don

I replaced most of the wiring on my bike, and highly recommend getting a new main harness, headlight harness, and front brake switch sub. I got a couple dozen tags with string attached, and labelled everything that wasn't coming off, like the handlebar and rear light wiring, marking the color of the wire it was attached to before removal if I couldn't hook up the new stuff immediately. Also, if you like the original bullet-style connectors (which I did) get an assortment of new (insulated female) singles and doubles (are there any triples? I can't remember), and definitely replace that big plug, which shd be located further forward than where yours is pictured.
I did mine mostly step by step, pulling off the old just before plugging in the new, in each area. Save your old harness in case you find a need later for another wire of a certain color, as I did.
The old female connectors (and even some new Lucas ones) are fragile and should all be replaced if possible. I broke several just plugging into them. There is probably a special tool for plugging them in if tight; I used a dental tool to push on the bullet instead of the wire in several places. Too much friction, you can pull the wire off the male bullet when un-plugging, too little and you have a shaky contact and probably a fractured female. I used Vaseline with good results, as well, and used just a few cable ties to keep stuff in place if there was a chance of it wandering.
It's a great feeling to get this sorted out and reliable. Good luck, and have fun!

thunderbolt said:

One more question, when the connectors are all plugged together under the tank, how was the wiring harness held in position? Cable ties, other protection from frame and other bits?

Click to expand...

Yes, use cable ties 'as required'.

Well worth running a decent earth wire to the headlight at least. Otherwise the headstock bearing has to conduct electricity if anything is earthed to the headlight. Best to avoid using the frame to conduct anything. I run fat red wire round all the components that need an earth straight back to the battery.

gripper said:

Well worth running a decent earth wire to the headlight at least. Otherwise the headstock bearing has to conduct electricity if anything is earthed to the headlight. Best to avoid using the frame to conduct anything. I run fat red wire round all the components that need an earth straight back to the battery.

Click to expand...

Unless thunderbolt decides to make his own harness (although not shown on the wiring diagram) the standard Commando harness contains all the necessary earth/return (red) wiring (for headlamp, tail lamp etc.).

Thanks guys, great information for me to now start removing the wiring from the frame with confidence,

All advice greatly appreciated,

Thanks again,

Don

Mr. Rick said:

I There is probably a special tool for plugging them in if tight; I used a dental tool to push on the bullet instead of the wire in several places. Too much friction, you can pull the wire off the male bullet when un-plugging, too little and you have a shaky contact and probably a fractured female. I used Vaseline with good results, as well, and used just a few cable ties to keep stuff in place if there was a chance of it wandering.
It's a great feeling to get this sorted out and reliable. Good luck, and have fun!

Click to expand...

Yes, there is a special tool for the bullet connectors


This tool is available from the usual suppliers, such as British wiring

I use a good pair of needle nose pliers to separate the connectors, pulling the bullet tip out of the connector without stressing the wire

You could make your own harness, that's what I did, affords you the opportunity to upgrade all the connectors to modern, convert to single point ground, and is really not that complicated as long as you diagram everything out and measure twice.

seattle##gs said:

since you will be connecting new wires to old stuff like coil terminals, headlight switch terminals, key switch terminals and old bullet terminals, there is some great stuff from the electronics industry called DE-OXIT 5 , spray stuff that really works and promotes good contact on old bits by actually dissolving old corrosion. it is especially good to get inside old female spade and bullet connectors where it is impossible to reach with a file or sandpaper. And don't forget to scuff up ALL your old grounds.

Click to expand...

An alternative to clean corrosion from wire:

removing-oxidation-from-old-wire-t19769.html?hilit=cartridge%20brass%20cleaner#p253577

Slick