Wiring Loom Layout

[AdrianJ]

I'm just fitting a new wiring loom to the plunger A10.
I didn't keep proper records when I took the old one off - though much of it was just a bunch of wires - all colour coded black!
A couple of questions:
Should the regulator connection strip be at the front  or the back? (i'm having difficulty arranging the nest of wiring which will be under the saddle).
Does the main loom run under the top frame tube or between the tube and the tank?
Any help gratefully appreciated.
Adrian

[Greybeard]

On mine: The regulator connections face to the front of the bike. The loom is under the frame top tube. I used cable ties to hold it in place. I was pleased to see the new loom I bought had earth return wires in it so I didn't need to rely on dodgy returns via the head bearings and the frame. Have you got the extension piece to go to the dipper switch?

[AdrianJ]

Thanks Greybeard,
Just what I needed to know.
Yes - I've got the dip switch part and an earth running to the headlight area. Where did you attach it?
It's one of the modern "Lucas" looms.
Regards,
Adrian

[Greybeard]

.. earth running to the headlight area. Where did you attach it?

For Earth, maybe we should say Ground or Return.
It was a while ago! Without taking the headlamp apart: I think the Return goes on one of the light switch terminals. Although having Returns in the loom should mean the frame doesn't need to be part of the electric system I attached the loom Returns to the frame bolt under the saddle.

[AdrianJ]

Yep! That's where I'm connecting them. Though it's taking a lot of sanding to get a good contact.
Checking with a multimeter and
I get 7 or 8 ohms between there and other adjacent frame points.
The headlight is OK with the return wire, but Istill need a frame connection for the rear and (I think) the dynamo.
Just need to establish a good connection.
As an old school electrical engineer, I'm happier with earth than ground, though in the case of this bike return makes more sense.
Adrian.

[Greybeard]

Ah yes, the dynamo uses the bike frame doesn't it.

[Greybeard]

I think my loom has a return for the rear lamp

[AdrianJ]

That's a good idea, but mine doesn't. Just headlamp assembly.
Thinking about it the dip switch and horn also have to use the frame.
Adrian

[Billybream]

Are you adding fuses during your rewire, very worthwhile protection.

[AdrianJ]

Yes, but just the one. 25A in the return to the battery.

[Greybeard]

I put a double fuse box in the battery feed cable. It's mounted on a small stainless steel bracket attached by one of the regulator box studs. I think they are 16 Amp fuses. You can also see my waterproof battery connector just below the fuse box. This is a 13AH battery and rubber case, (from Paul Goff). There is very little room between the battery top and the case lid so I've soldered wires onto the battery tags and have a connector, as shown.

[Swarfcut]

Adrian, 25A is a bit heavy a fuse. 10amp will just about cover a full load, 15amp allows a bit of margin. 25amp  and the wiring stands a better chance of frying before the fuse blows. I used one of the battery carrier studs as a central earth point and like GB, added an extra return from the rear light assembly, as getting a good rear mudguard/frame electrical connection is always awkward especially with powder coated and  painted parts, seems a pity to go scraping off newly finished items.


 Swarfy.

[Greybeard]

Thinking about it the dip switch and horn also have to use the frame.

Dipswitch no, not on mine anyway. There was a short piece of loom to go from the headlamp to the dipswitch.

The Horn on my loom has a return wire. You can see the wires coming up from the horn in the first picture above. There is also an alternative horn connector spur beneath the petrol tank.

[AdrianJ]

You are correct - there's no return on the dipswitch just the two live leads to the bulb and the supply.
I can easily change the fuse. I thought 35W for headlight  - 15 + 10 for rear and brake + 15 + 10 for lights on chair = 85W
This should be about 14A which I approximately doubled as a safety margin. I've probably overestimated.
I have two 6V batteries in parallel in a rubber case with plenty of room for the fuse holder as well.
Adrian

[Greybeard]

I've just been working on the mag kill button. That has its own wire to the mag and just earth's to the handlebar.