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[Zelda]

Dear RE friends,

As some of you may have seen, I had previously asked the forum about troubleshooting my charging system. I recieved very helpful feedback, which has now resulted in my decision to re-wire completley. I beleve the issue was related to an unclear wiring diagram and a shorting lightswitch.

I would therefore like to ask if anyone can provide me with a wiring diagram for a 12v installation? The bike has a lucas alternator (Paul Goff provided) and points ignition. I will replace the lightswitch, reg/rectifier and battery according to the diagram's reccomendations. Even the coil if suggested. I will need to make the loom myself, so any suggestions on how to approach that and wire gauge would be of great help.

Many thanks in advance, and perhaps see you at the 70th anniversary if we have success!

[stinkwheel]

I made my own wiring diagrams and loom for my 612 bullet.

I find it helps to break it down into systems. Broadly speaking Ignition. Charging. Lighting. You can do a wee sketch for each system then bring them together in one bigger diagram.

Vehicle wiring products are very helpful. They supply most of the stuff you could need. You'll need to chose a connector type, that may be slightly oddball bullet connectors if you want to be in keeping with your older bike and to connect to the original fixings. Buy the proper crimping tool. That's an essential.

You can get standard and thinwall cable. The thinwall carries a lot more current for thinner cable BUT I find the crimps don't always grip the insulation adequately.

You can spend a long time working out differing cable thicknesses and ordering a job lot of colours. In reality. If you add up all the bulb wattages that could be on at once, that's going to give you a working maximum current and you can probably work with all the cables at that thickness anyway.

I went one further. I worked out I could make the main loom with only 8 wires so I ordered a long piece of 8-core cable of the appropriate wattage and a length of black cable (which I used for earths). The 8-core made the main part of the loom (and I also used it to make a sub-loom for the taillight area). I stripped the insulation off a bit of spare 8-core to give me an assortment of coloured wires for the "birds nest" in the headlamp.

Here's my main loom diagram (remember this is for a bullet with an aftermarket charging system, Honda switchgear and LED lighting):


Here's a sketch I did once I had the wiring colours to show the main loom (you don't know colours until the multi-core arrives).



When I did mine, I laid the earths separately, all in black and looped them all both to the frame AND back to the battery so there is insulated return AND frame earth. Lots of ring terminals

[Adrian]

OK. a fresh start on the electrics is probably a good idea.

A few questions first, though.

1. Single or three-phase alternator from Paul Goff? He sells both sorts.

2. Will you be adding indicators?

3. EXACTLY what switch gear (lights/ignition/horn/dip) will you be using? Direct replacements for the originals or something more modern?

The wiring will very much depend on what is happening with that lot. If you are going to fit like-for-like in place of the original switches a simplified version of the original 6V wiring diagram will be enough, if not something like a modified version of the BSA A65 wiring will be needed, depending on what is fitted.

http://www.motobrit.com/motc2/mphp/phot ... 1967-1968)

I think it was suggested earlier that you keep to the correct period Lucas colours for the wiring, I'd want it to be able to cope with 16A, and our hosts sell all those, but in 10m lengths, which is more than you will need.

http://accessories.hitchcocksmotorcycle ... le?&model=

The budget alternative would be to use a 3m length of 10 core cable of the correct rating in different colours, all conveniently fitted in a black outer plastic sheath, which you can get here:

https://www.ebay.co.uk/itm/10-CORE-AUTO ... 1125011570

10 core will be enough to allow indicators to be fitted if you wanted them. You would of course not be following the original Lucas colours, up to you to decide whether that is an issue or not.

I'd also avoid pre-insulated terminals for the wiring connections, 3.9mm Japanese-type bullet connectors with slide-on insulation are better, unless you're insisting on Lucas classic 4.7mm bullet connectors.

A.

[Adrian]

Stinkwheel beat me to the draw!

That looks like an Electrex World CDI system, which might be muddying the water somewhat!

A.

[stinkwheel]

Yes, electrex loom for me which does, as you say, muddy the water. I was however using it more to illustrate the thought process and that it needn't be too complex.

The more observant may have noticed I had the ammeter in the wrong place on the first diagram. It wouldn't have shown charging current, only discharge. It needs to be between the battery and the charging feed.

[stinkwheel]

?Interestingly? I once did an empirical scientific test to see which terminals got the best hold. One of my bored moments.

I put ring terminals on the same thickness of wire using pre-insulated crimps and 3.9mm non-insulated crimps. The former were applied with a ratchet crimping tool. The latter with a crimping die.

Then I hung them off my workmate using a nail through the ring, tied a bucket to the end of the wire and started adding water. The non-insulated crimps would let go after about half full (so between 7 and 10 kg). The pre-insulated ones hung in there with a full bucket so I had to empty it then put a couple of cast steel weights in the bottom and start again. They all exceeded 20kg of pull. The ring terminals ovaled with the weight.

So. I can only conclude that pre- insulated terminals are stronger than their non-insulated equivalent by a factor of 3. WHEN APPLIED WITH THE CORRECT CRIMPING TOOL not pliers.

The above notwithstanding, I still use non-insulated on my own bikes. The others seem inelegant and you can solder fully mobile of fully stationary ones over the crimp.

What IS a good thing to do with your terminals is to apply silicone grease to them all prior to assembly.

[Zelda]

Hi Stinkwheel and Adrien,

Thanks for the reccomendations, especially the pointers on where to purchace what I need. I think the 8 core will do for me and i'll make a new diagram just for the bike.
To answer your questions;

1. Single phase 12V 200W 2 wire (RM27)
2. No indicators
3. Lights are original but 12v (x2 pilot, main and full front, rear and break). 12v Ignition coil, I have the previous installed but also a new lucas one if needed, original combined horn and dip unit.
The battery has been abused with being left standing for long periods of time and occasional charging, so I could replace that with someing suitable if you have a suggeston? Previous was 12v5Ah gel.

An issue I had which was identified on a previous post was related to the light switch wiring. I would therfore like to replace this too to enaure i've got the right set-up. On the original wiring, the pilots came on alone, and then went off with the main beam on. My incorrect switch kept them on with the main and potentially earthed.

To be decided is which reg/rec to be installed and what diagram to follow. Presumably the original 6v diagram won't be so helpful here?

[Adrian]

OK, you have a high-output single phase alternator, so that needs a single-phase reg/rectifier which can handle all that output. Nothing quite butch enough for that on our hosts' listings, unfortunately, so it's over to (e.g.) Rex's Speed Shop for one of these:

https://www.rexs-speedshop.com/product/ ... rectifier/

Paul Goff and Al Osborne will have something similar.

For the light switch, given what you have in mind, I'd replace the original with one of these, pt. no. 140844 from our hosts, as a direct replacement.



These were originally 6V system switches which means they will have terminals that a 12V system won't use, but will work just fine.

Actually the original 6V wiring diagram will be a lot of help, because it will form the basis for a (much simpler!) 12V system. Briefly you replace the old rectifier with your new super-duper reg/recifier and remove all the bits of wiring associated with switching in extra alternator coils for the headlight, as on your 12V system the alternator is permanently wired for full output. The ignition switch becomes a simple on-off switch, and so on.

Our friend Scalyback has kindly posted a lot of stuff on-line, including the original diagram with coloured wiriding marked accordingly.



Now study this for a while and I will suggest how we can 12 volt this in a moment.

A.

[Adrian]

Now let's think about fitting your new charging system into this.

Your alternator will have just two wires, each of which will connect to one of the yellow wires on the new reg/rectifier unit.

If you're keeping it positive earth, that will be the red wire from the reg/rect, so you can ground that to the frame with a suitable ring terminal somewhere. The black wire will then need to hook up to the ammeter where the brown and white wires go.

Now we can get rid of the old 6V charging wires, perhaps best to print off the diagram and get some Tipp-ex™

From the ignition switch delete the following:

Green and yellow wire to the alternator, terminal 11
Yellow to the lighting switch, terminal 13
Purple to the rectifier, terminal 2

From the light switch also delete:

Dark Green wire to the rectifier, terminal 1
Light Green to the rectifier, terminal 7

All we need now is a suitable fuse fitted in the brown and blue wire somewhere near the (now 12V) battery on its way from the ammeter and some extra red wire for additional earth leads from the stop/tail lamp and the headlamp relector unit back to the battery. Headstock bearings don't conduct electricity so well.

A 12V horn and you're pretty much there, my learned friends will no doubt suggest any improvements/omissions.

A.

[Adrian]

Oh yes, I'd go for a Motobatt AGM battery, look 'em up on-line and find one the same size as your original or slightly smaller if rhere's no exact size match.

A.