wiring isues HELP

[Buster1450]

Hi Chaps.
I hate electrics they are the Devils work.

I have just put I new wiring loom on my 1960 Golden Flash swing arm with a side car.
With the bike not running all the components work as they should and with the lights on full the amp meter reads -5 however with the bike running the amp meter stays the same for about a minute then when I rev the engine it slams down to -8 and the negative wire gets hot.

Can anyone help?

[bsa-bill]

I'm no expert on the subject but sounds like maybe your dynamo is polarised wrong way around or your voltage regulator is off.
First thing I think would be to check your dynamo, remove the wires from the dynamo then connect both output tabs together with one wire and with the motor running check what voltage you get with a meter from this wire to earth ( bare metal on frame ) more important is the polarity you should get a reading with the positive lead of your meter to earth and the negative to the dynamo, If you get no reading swap the leads around and try again if you get a reading this time then your dynamo is wrong polarity

Try this then get back to us, more informed members may have better suggestions, you may need to flash the dynamo, sounds dramatic but is easy, must be I've done it

[Buster1450]

Hi Bill,
I have checked the polarity of the Dynamo and it appears fine +7.4 with the negative terminal of the meter on the dynamo wire and the positive to earth.
Any more thoughts?
Looking again at the wiring diagram there is a few differences,

1. the diagram has an earth direct from the horn /dipper switch, I have the earth from the back of the headlight fitting as the horn push has no earth terminal.

2 the loom has two brown and white wires running to the back of the loom towards the tail light not sure what they are for as they don?t appear on my wiring diagram.

?

[Buster1450]

Hi another little piece of info.
With the bike running and when I increase the revs the regulator trips and cuts all the lights and stops charging that?s why the amp meter is showing -8 .

Is the regulates faulty ?

[iansoady]

It does sound like a regulator problem - as though when it cuts in something is being earthed.

Make sure the frame isn't earthed as it's supposed to be floating.

Attached is the Lucas manual for the earlier type box although they all work the same.

[Buster1450]

Hi Ian,
Thanks for the reply,
I thought the frame was the earth? Not sure what you mean about it being floating.

I have ordered a new control box today.

Regards,
George,

[Buster1450]

I have solved one of the issues the two  brown and white wires that come out of the back of the loom were joined by a snap joint, I separated them and that has stopped the ammeter plunging down to -8. Now when the bike is running the amps are steady at -6 but it is still not charging the Dynamo is ok so it dose point towards the Regulator.
I will let you know if the new one cures the charging issues.

Later,

[Stu55Flash]

Buster

Did your bike work ok before you changed the wiring loom. Where there any charging problems etc.I would check you have the correct connections to the reg. Field, Ammeter Dynamo Earth. Some are FAED.

Stu

[iansoady]

Hi Ian,
Thanks for the reply,
I thought the frame was the earth? Not sure what you mean about it being floating.

I have ordered a new control box today.

Regards,
George,

I'm referring to the frame of the regulator - you can see from the circuit diagram on p1 that the dynamo connection goes straight to that. Although thinking about it I don't think that would give you the problem you're experiencing.

[wilko]

Take the dynamo chain off and motor the dyno to make sure its polarity is right.