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Wiring again

Since there has been discussion about “wiring” I thought I’d right up a tutorial on how “I” do it. (I’ve done about 3 dozen over the years, starting with readymade looms. Which to my mind are a waste of time and money, with wrong connectors which are often in the wrong place or not needed at all)

The original cable was black rubber with just colour tags on the ends. (For these I use small lengths of different colours of shrink wrap) I’ve been fortunate for many years to be able to buy silicon rubber cable that replicates the original (But it seems hard to find lately.) Ordinary black plastic cable can be used with the bits that show emeried or scotched to remove the gloss.

I always start with the regulator which has four terminals held in with hollow tube connecters ( the terminals are marked F A D E) . Before I mount the regulator to the frame, I connect three lengths to F D and E long enough to reach the magdyno area and one length to A, long enough to reach to the headlamp. Ultimately F&D are connected to the corresponding terminals on the dynamo and the E (Earth) wire is connected to the grub screw at the bottom of the mag. A further shorter wire is connected to the grub screw and goes back to your battery Neg (earth) terminal. You can clearly see how it goes in this B&W RE picture. Although lots of guys prefer to make the earth points by nut and bolt to a convenient part of the frame.

Once the regulator is mounted and it’s wires connected. I then concentrate on the headlamp. I run four wires only to the headlamp through about 18” of rubber sheath (Old bicycle inner tube) The long “A” wire from the regulator which goes to one side of the ammeter, then another similar length from the other side of the ammeter back to the battery Poss terminal. I run an earth wire from the headlamp which can be connected directly to the battery or a convenient earth point on the frame. The final long wire goes from the headlamp down the right side of the bike to the tail lamp.

The wiring diagrams will usually show the live feed for the horn coming from the headlamp, but I think it’s congested enough, so run it directly from the battery. I also slightly modify the wiring by taking the Regulator “A” wire directly to the ammeter then a wire from that terminal on the ammeter back to 3 on the light switch. That way I am only trying to squeeze two wires instead of three into the awkward grub screw terminal.

The wiring diagram shows how all the wires are connected to the light switch and bulbs. The horn is earthed via the horn push on the right side of the handlebar. Finally a brake light switch can also be added to the left side of the bike.

It’s not rocket surgery!! I'm open to questions and debate. Ron


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Re: Wiring again

Thanks for this Ron. Well written.
One idea (coming under the heading of "I wish I'd thought of that") I got from the German BMW site I look at is to paint the inside of the headlight white. Not original but it gives a bit more light when tinkering. Though of course with a Lucas switch you can take it off the bike to work on, can't do that with a BMW.

Re: Wiring again

Hi Ron, seems I tought you well!



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