Wire, Connectors, and Such

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Feb 22, 2007
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About to launch into the electrics on this bike. I've cut away the old, rotting harness. Was wondering if anyone could recommend what to buy in terms of:

1. I'm guessing four different "colors" will do the job;
2. Amount of each (color) I should buy;
3. Best gauge to do the job;
4. Fuses? Circuit boards?
5. Number of connectors, separated by type (okay, I'm being particularly harsh here); and, finally,
6. Where to buy?
7. Or not? Have I got it all wrong? Just buy a harness and modify to fit specific applications?

Am I being demanding or what? Sorry.

Would like to be efficient but not cheap, as trips back to the supplier cost money as well. As a complete and utter amateur to vehicle wiring any advice is welcome.

I know I'm not being overly precise here.... hopefully it's making sense to someone :shock:

wrench

PS This is what I'm not after.

Wire, Connectors, and Such

PSS My forks are done (awaiting head light mounts), my head steady is fastened, the frame has been identified, etc., etc. I owe it all to this forum. I am very indebted, obviously..... Can't say thanks enough.
 
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I think CNW uses 16 gauge marine-rated primary wire in their restorations. I used regular 16 gauge primary automotive wire in different colors from the local auto supply place. Seems to work fine. I think you will need more than 4 colors. Do you have a wiring diagram? All you really need is one main fuse off the battery. Mine comes off the negative side and I have postive ground. Are you using a Boyer ignition, solid state voltage regulator etc? If so, this simplifies the wiring harness considerably. The stock harness will have a lot of leftover wires if you are running electronic ignition etc. I would recommend soldering all connections and wrapping with tape and/or shrink tubing. You can also put a plastic sleeve over the wire bundle from back to front of bike to keep things tidy. I would also recomend running grounds to everything from a common ground rather than relying on the frame for the ground. Good luck!

wrench said:
About to launch into the electrics on this bike. I've cut away the old, rotting harness. Was wondering if anyone could recommend what to buy in terms of:

1. I'm guessing four different "colors" will do the job;
2. Amount of each (color) I should buy;
3. Best gauge to do the job;
4. Fuses? Circuit boards?
5. Number of connectors, separated by type (okay, I'm being particularly harsh here); and, finally,
6. Where to buy?
7. Or not? Have I got it all wrong? Just buy a harness and modify to fit specific applications?

Am I being demanding or what? Sorry.

Would like to be efficient but not cheap, as trips back to the supplier cost money as well. As a complete and utter amateur to vehicle wiring any advice is welcome.

I know I'm not being overly precise here.... hopefully it's making sense to someone :shock:

wrench

PS This is what I'm not after.

Wire, Connectors, and Such

PSS My forks are done (awaiting head light mounts), my head steady is fastened, the frame has been identified, etc., etc. I owe it all to this forum. I am very indebted, obviously..... Can't say thanks enough.
 

L.A.B.

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wrench said:
1. I'm guessing four different "colors" will do the job;


As tpeever said, you will probably need more than 4 colours, although you haven't said what circuits and systems you intend to keep?

Flashers/indicators/blinkers probably may not apply to your '71 model (but the flasher warning lamp is apparently there in your harness photo?) and you may want to remove the assimilator or warning lamps etc.?

So I would think it wise to use different colours for the following:

1. Ground/Earth

2. Main battery wire (to Ign. SW)

3. Ignition feed

4. Contact breaker L/H cylinder*

5. Contact breaker R/H cylinder*

*if electronic ignition is fitted then you may still need these two wires?

6. Lighting (tail lamp, feed for H/lamp and speedo/tacho illumination [front position/pilot lamp if applicable?])

7. Brake lamp

8. Horn (from switch)

9 Ignition Sw. to H/bar switches (horn/headlamp flasher), front brake Sw. (if applicable?).




wrench said:
2. Amount of each (color) I should buy;

Not knowing how you intend to lay everything out it can be difficult to say how much of each colour you will need. Generally a couple of yards (or mtrs.?) of each colour would be enough, but you will need to either buy too much or work it out carefully, the hassle factor of not having enough wire and connectors (or enough colours) to finish the job really isn't worth the aggravation!
 

Ron L

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Much depends on what modifications you have done. Three-phase alternator? Solid state regulator/rectifier? Do you plan to use relays? Do you plan to use a small fusebox for fusing individual circuits?

Draw your circuits first and label wire colors. Use plenty of good ground wires.

I would advise buying wire in the original color codes. This way if you sell the bike or some one else works on it they can recognize what the wire does. (i.e., blue with different tracers for lighting, brown/green for instrument and taillight, etc.). This is available in modern insulation from British Wiring (http://www.britishwiring.com). Minimize the use of connectors, but use enough to be able to remove the harness from the frame without cutting.

Use shielded spade connectors, molex connectors, or weatherhead connectors where possible. Soldering is best, but a good crimp with shrink tubing will do the job.

I am a proponent of using relays for headlight, horn, and ignition feed (to eliminate current to electronic ignition running through the handlebar kill button). I also fuse these circuits separately so a short in the headlight or horn will still let you ride the bike home by pulling that fuse.

My $0.02.
 
Joined
Apr 7, 2004
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I use the stock colors they are all listed here. http://www.britishwiring.com/CAT06_07.PDF
www.britishwiring.com has all the stuff to do a proper job.
Anyone later trying to check something should be able to look at a diagram and see what you have done. Triumph's,BSA's and others use the same basic colors. As you look at different schematics for different years and brands you will see the theme repeat itself. Use the theme. I use the crimp tool and male and female bullets they look right and work well.
They also sell pre-made harness.
 
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It seems that everyone is telling you the same thing. That is good!! The first thing you need is to decide what electrical circuits you need and then you need to decide how stock you want the harness and connectors to look etc. and if you want to improve the setup with relays etc. After you have decided all this, then you need to draw yourself a good diagram. I have rewired three Brit bikes now. The first two were running Boyer ignitions and have signals. I used the stock cloth-covered harnesses (from British Wiring!!) which look nice but had a lot of extra wires that I had to tape out of the way because I had converted everything to solid state. The third bike I rewired totally from scratch in non-traditional colors but was careful to draw out a good diagram with all the color codes on it. This way, someone else can easily figure out what wire goes where. However, if you want to stick with the standard Lucas colours , British Wiring is a great place to buy your stuff. I have bought a lot of things from them and they are great people.

Have fun!
 
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Feb 22, 2007
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In here LATE tonight, and will read your posts more thoroughly tomorrow. Suffice it to say now, just a huge thanks. Just what I was looking for. Your experience gets me thinking along the right lines and saves SO much time. Cannot say how thankful I am, and how much I love working on this bike.

I'm leaning toward the three phase alternator, may invest in the Pazon ignition, but not sure (have a Boyer on the shelf) , I'm just learning about the importance of relays, and, and, etc., etc. It's all new to me, but I consider this a good thing. The Commando deserves my full attention, me thinks. At least in the pittance of time I can give her after a day's work.

Seriously, THANKS. I'll be checking in soon with more questions and comments.

wrench
 
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If you choose to go with a negative ground system. Just buy lots of black wire instead of red.And look up some Triumph and BSA harness diagrams to see the common wire colors that they use again and again. All of the extra grounds should run to a common spot on the frame it seems the best spot is the hole for the rectifier, and don't forget the battery in this common ground.
 
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Feb 22, 2007
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Thanks for the help and tips for this. Looks like British Wiring is the place to go for supplies. And I will check into old diagrams to see what colors are traditionally used to keep the bike consistent, although I will not be going the harness route owing to the custom aspect of my project. And I'll definitely be using relays whenever possible (great advice). And the break-down of different colors listed is, obviously, a very good and big tip as well.

I'm still having something of a mental block regarding the negative versus positive ground.... for some reason, most of the stuff I'm reading assumes the reader already knows the difference. Are their strong arguments for or against either one?

This is all a huge help. Thanks again.

wrench
 
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Positive or negative ground is equivalent. By tradition, most (all??) British vehicles used positive ground. All the British motorcycles I have seen are positive ground. I think some of the mid to late 70s Triumphs converted to negative ground but am not sure. Most of the wiring diagrams you see for British bikes assume positive ground (red wires) so keeping your bike positive ground might be easier in the long run. I have stuck with positive ground for my bikes.

A more important point that others have mentioned as well is not to rely on the frame for grounding at the bikes extremities. Run a ground from a common position on the frame near the battery to the front and back of the bike. Also attach the battery directly to this common grounding point. Then you want to attach the ground side of all your electrical gear (headlight, taillight, blinkers etc.) to one of these wires instead of to the frame. That way, you will be assured of a good ground to everything.

wrench said:
I'm still having something of a mental block regarding the negative versus positive ground.... for some reason, most of the stuff I'm reading assumes the reader already knows the difference. Are their strong arguments for or against either one?
 

L.A.B.

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tpeever said:
By tradition, most (all??) British vehicles used positive ground. All the British motorcycles I have seen are positive ground. I think some of the mid to late 70s Triumphs converted to negative ground but am not sure.

A large number of older British motorcycles were in fact wired Negative Earth/Ground until shortly after WW2, when Positive E/G seemed to be almost universally adopted by British manufacturers.

Triumph changed to Neg. Earth for the 1979 E models that had a three-phase alternator and Rita ignition.
Although the change could have had more to do with market forces rather than any technical reasons?
A Positive Earth electrical system apparently causes more chassis corrosion than a Negative Earth one.
 
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tpeevrt, L.A.B. (and all)

Thanks again. It's all a huge help. I'll be ordering wire sometime in the next week or two. You'll be reading some more silly questions soon after that. Thank you for taking the time to educate on topics that must be quite mundane considering your experience/skill level. Mucho appreciiated.

wrench
 
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