All new loom and lights wiring,

[MrShifta]

I am struggling with wiring my RGS replica.  I bought a new Lucas ( Chinese ?) wiring loom with a colour coded schematic diagram.

It looked good so I laid it out on the floor and labelled every wire as per the diagram.  The headlight is 50 years old and new in the box but could be pattern, the dynamo has been rebuilt, the Lucas regulator was a recon unit from Lucas 50 years ago and never used. The rear light is original but works fine. The battery is new.

My problem is that after installing the loom and carefully connecting all labelled wires to their components I have no power to the ammeter.  I have 2 pink wires in a single bullet sleeve ( shown as brown on the diagram) at the battery end of the loom which appear to do nothing ? and a a pair of pink wires at the headlight end doing nothing.  There is no continuety between them .

If I connect a loose wire from battery Pos.  to the ammeter everything appears to work. I have not had the engine running yet so the charging side is unchecked but is all connected as per diagram so should work.

What am I missing ? why is there no 6v pos to the ampmeter.  The diagram shows a red wire entering the loom at the battery end, however There is only the pair of pink wires. If I connect the battery to them the stop light works but nothing at the ammeter end.

Is there anyone living within striking distance of me in Sutton on Sea, Lincs, LN12 2JB who is willing to help ? I am happy to pay a reasonable price as I am out of my depth.

There is no tatty wiring or parts so no poor connections.

Thanks for any help offered.

Barry
 








ammeter

[MrShifta]

Picture of the Lucas diagram and a circuit downloaded from elswhere. 

[MrShifta]

This appears to differ from the schematic ?

[groily]

The harness has been made with the purple from regulator A going direct to T3 of the switch, with a separate wire from there to one side of the ammeter. Wherever it was made, there's nothing obviously wrong with it if the materials are of adequate quality.
In the schematic, the purple from A goes to the ammeter and then there's a short purple from the same side of the ammeter to the switch. Truly, no difference - purple to switch T3 then to ammeter, or purple to ammeter then switch T3 comes to the same. One way you get 2 wires on T3 and one wire on that side of the ammeter, and vice versa the other way.

The other side of the ammeter goes to battery live. That's the brown wire - which is connected inside the harness to the main red one at the battery end. It emerges from the harness at the same place as the short purple link from T3. Or are you saying it isn't there??

Which side which wire goes on the ammeter you will see from whether you get a + or a - reading on the needle when you switch something on. If the wrong way, swap the wires.

If the brown wire intended to go to the ammeter  isn't connected to the ammeter, then there'll be 'no power' from battery to anything except the horn and brakelight probably (by virtue of their separate feed from the battery). If you've connected the brown to something else, it needs repositioning!

So, if you follow the harness markings on the main bits, you'll be fine. The pink wires you mention have to be the feeds for the tail /brake or side/speedo lights I'm guessing. But they aren't the main brown wire that needs to go to the ammeter.
The only thing I, and most others here, would do without any discussion hesitation or deviation , is PUT A FUSE IN. On a 6v system, a 15A one minimum, in the battery live side, to cover brake light and horn as well as the main feed to the switch. For the modest hassle and the very modest cost, worth every penny compared to the consequences of frying the wiring and maybe the whole bike / shed / house / street!

[Swarfcut]

Barry. It may be worth identifying each wire individually for continuity, and also to avoid any mis identification of what goes where. With the brake light and horn, the usual practice is for these to be on their own circuits. On the circuit shown the horn feed comes off the battery side of the ammeter, so horn use will not register on the ammeter.  With a charged battery this still gives two basic safety features in the event of other electrical failure such as a burnt out ammeter. Mr G's recommendation for a fuse is one I would not be without, a simple inline type is fine.

 Swarfy.

[MrShifta]

Thanks guys, I do have a fuse in the battery pos. wire.  It came with the loom with bright red wire out of both ends. One end had a tag to connect to the bettery and the other was a bullet.  There was no red wire from the loom to connect the red battery wire to. The only other bullet was the pair of connected pink ( brown ? ) wires which feed the stop light.

I was beginning to think there may be a red wire buried in the loom at the battery end.  I have exposed a section of the main loom after leaving the battery end and becomes one single braided loom under the tank.  There are a pink, a purple, a green and yellow ( dynamo) and two blacks. There are no red wires going to the headlight/ammeter in the loom.

No brown wires either,  I wonder if they ran out of red or browm wire and used pink instead ?

I am tempted to run a pos. wire from battery to the ammeter alongside the loom and run the engine to see if everything works.  I suppose there could be a mistake in the loom.

[RDfella]

Looking at the Lucas diagram doesn't help much either, as the red is confusing at both ends.

Add: The footnote says 'trust Lucas'. Why change the habits of a lifetime, especially when faced with a rubbish wiring diagram like that?

[groily]

Hmm! Buggered if I know if they haven't followed their own colour code, so you'll have to do what Swarfy says and see which wires are continuous.
Whatever, you need a decent wire direct from battery to ammeter, opposite side to where the A wire from the regulator and the link from switch T3 go.
Greens and Yellows are easy - F and D. Blacks are presumably earths as you're neg on that front. For side and speedo and tail I'd follow the schematic as it'll give you tail and speedo with front side and keep the tail and speedo on with the headlight (without front side).

You'd think people could make things that match their instructions, or at least alert us to any variants  . . . . No wonder many folk never believe any colours on anything go anywhere near where the published diagrams suggest they might!

[BSA500]

OK I looked at mine which is the same as yours the red positive fuse wire plugs into the pink bullet connector

[MrShifta]

Thanks lads for all your advice, I haven't had a look for a few days due to " family matters"  I spent today with two meters, one set for continuity and one for voltage.  I cut into the loom at the battery end and found a pink wire which was continlous to the pair of pink wires which connected to the ammeter.  I sliced the pink wire and attached it to the battery positive.

Everyting now works, horn, lights, stop light but still not started it yet, by weekend I should be ready for the big fire up.

Fingers crossed.