Light switch

[Bamboo812]

Do you hear a clicking from the headlight relay when you switch from high beam to low beam? Could be the relay is sticking.

[Porge]

Getting nothing with jumpering what I presume is the main circuit. Light click with the park.

[Airbear]

G'day Andrew
Once you get the switch working ...

The 1975 and beyond bikes have what is called a 'Light Relay'. It is not used in the way one would expect from a normal headlight relay. Full power for the headlight still goes through the 'dipper' switch in the perch so no benefit in saving the contacts or avoiding the usual voltage drop. I still don't know why it is there - I have heard that it is possibly there to turn the headlight off when starting, and another view is that it is something to do with some weird parking light legal requirement - perhaps somebody more knowledgeable can help with that? There are also the UK/US differences to sort through in the diagram. Good luck with that.

I am by no means an 'electrical guru', by the way, just interested. I am afflicted blessed with a proper 1974 /6, before they 'fixed' things, and the wiring actually makes sense to me.

I believe the 'Light Relay' can be deleted but don't know the details. It is certainly beneficial to add a proper headlight relay(or relays) to get the benefits. May the gods be on your side.

[Chuey]

Sorry to be late to this discussion. I would have gone to a bicycle shop and asked to buy one each of the two smallest size balls they have. It would be one of those almost certainly.

The detent function is, indeed, what the ball is for. I've taken apart one of those switches but the memory doesn't stay since it seemed kind of simple and primitive and I figure I'd figure it out next time instead of overloading memory with it. The electronic part of it is mostly mystery to me, though.

Chuey

[Porge]

I'm beginning to think there's been something missing inside, as there seems to be no "mechanism" to carry current from the common terminal to the light circuits. Was tempted to wire in a mini DPDT switch to get her running....but came across a better looking switch from a working bike in Australia. Have it winging its way here. Will get the headlight shell apart to check the relay when shed time permits.

[Slashsevenpig]

Full power for the headlight still goes through the 'dipper' switch in the perch so no benefit in saving the contacts or avoiding the usual voltage drop. I still don't know why it is there

Some of the quirks of these machines suggest to me the era and the national heritage of the manufacturer. For example, Germany is home to the Autobahn. Is/was there a daytime running light requirement back in that era? Was the headlight switch standard equipment, or was it supplied to certain markets? If not, is/was it an accepted practice in Germany to flash the high beams, sans running lights, behind someone in the fast lane who isn't keeping up with the traffic flow?

I sometimes think of the national heritage of the manufacturer when I'm slogging through slow-moving traffic, trying to find a gear where the engine sounds happy.