classic motorcycle forum

howdy all,
I'm putting a (lighting) electronic ignition kit onto my Sun, it was wired as a rectified circuit.  The wiring diagram that comes with the kit doesnt mention where the ammeter hooks up - does anyone know where I wire this into.
The diagrams I'm working to are as attached

Where is the preferred/generally accepted location when adding in a rectifier (the square jobbies as sold by villiersservices etc.)?

I've no idea where the original would have been mounted on my SUN as all sorting in missing from it but I can see various potential places (some better than others! ) such as under the seat / up under the tank / in a tool box / in the headlight / bolted to the battery carrier somehow?

Does it need to be isolated electrically from the bolt/frame that goes through the middle of it when it's mounted (guessing not but after confirmation)?

Thanks!

A battery in situ, as it were ... ?



The 'de Luxe' tag may indicate it has a battery ?

You're onto something there - especially with that image! there isn't any lugs/holes for a battery on the frame so I'm guessing its a clamp around the seat tube battery cage affair....something for another thread, or maybe I rename this one! 

Thanks for the image - all helpful stuff!

Only the battery models would have needed/used an ammeter ?

good point - mine has an ammeter but no battery, that said I'm still learning what is missing from the bike, what it should have had on it and also what its had added to it!

MU42 is the common type where the switch panel (inc ammeter) is mounted on top of the shell, and often seen on 1940s bikes. I wouldn't think this would have been original for a post-war lightweight though.

Both shells I have have the same fitting for the switch panel and ammeter so I could move them over - they are different in design though with regard to how the rim is held in place, the 6 inch one has a notch and also a hole at 12 O'clock, a slight flared section from about 4 to 7 O'clock, a cut out at 6 O'clock and another at 11 O'clock - I've tried to take some more pics of the shell that I think is the correct one (the smaller one).

https://photos.app.goo.gl/tk1XNbUCVN7kFMdQ6

https://photos.app.goo.gl/AeKwh62ux3ASoVsv6


The larger Lucas shell is clearly different in the rim design
https://photos.app.goo.gl/LjJU4ZxLg9CpZPMw7

Perhaps we should have begun by asking precisely what bike/year/model this was for.
No chance of wrongly assuming anything then ...

It's a 1953 Sun challenger (plunger) 197cc. A far as I know its the original light shell. I didn't mention make /model as Sun info seems to be sparse at best!

Nothing, a) because I'm sensible enough to slow down when I hit a 30mph zone or near a school etc where there just might be 1:100 chance of a copper with a speed gun and b) neither me nor anyone else I ride old bikes with is going to ride on dual carriageways, motorways etc at a speed over and above that of the surrounding traffic....if at all.
Having a working speedo is nice, but we're not talking FireBlades or Hayabusas here. You've really got to try to break speed limits on a pre-war Ariel or Panther...

From my perspective it was more passing an initial MOT to get the bike registered again, I guess (possibly wrongly?) that any road going vehicle needs to have a working speedo and I suspected a bicycle one may not 'pass the test', if people are using these then its an easy win!