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Hi Jordan, I have a selection of used coils ,so at this point just interested in Identifying what I have. I will be getting into the flywheel to clean, adjust< and lubricate the points cam and the auto advance thats on the back of the plate . I will take photos then . Happily the system is working very well at present but sitting idle for many years it will need some attention. Its an AC system as there is a rectifier in there for the battery side of the coils.

I would call your system DC.
The coil in question: Is it mounted inside the engine cases or on the frame?
A rectifier is part of the charging system and doesn't prove it is a battery/coil ignition you have - but it might be.
Or it might have a battery-powered lighting system and a non- battery dependent magneto for ignition - similar to Ducatis with CDI.
Do you have a manual or wiring diagram?

Re: your used coils collection: I don't know how to be certain if they are Kettering (battery-coil), energy transfer ("magneto") or CDI types.
I tend to just try it and see. However, I notice Kettering coils usually have higher primary resistance.
Check out the video link I sent.

This bike will run ignition and lights without a battery , but is fitted with a battery for better lights when going slow. the coil is similar to one in a 125 lambretta and is mounted on the points plate

I guess the lighting coil (not the ignition coil) is used to charge the battery via a rectifier.

Does the ignition coil have a thick lead direct to the spark plug, or does it go to an external coil first?
There are so many variations!

You can measure the resistances of your working ign coil, get some data from that.
See the video for methods.

Three things:

Your bike may have a system like the Monza Jr. where the sparking coil, front headlight and rear running light may be AC and the brake light and horn are DC. It's a great setup unless you want to use LED lights. It that case all DC is needed.

Here is a good thread describing the AC and DC coil differences. viewtopic.php?f=3&t=3776&hilit=coil

If you find you have a dc coil you can hook up a battery to start the bike and then test each stator wire to determine the voltage and current. With that knowledge you can then figure out which stator wire goes to which function (sparking, running light, bake lights, horn). Good luck!

I have had a look at the bike and it has a frame mounted coil . It also has alloy levers in fixed steel perches on "ACE " type bars .These are angled too far from the grips to be practical , On old brit bikes i have used spare chain links to re-position the levers but this would look all wrong. Some Ducati's have similar issues ,anyone come up with a neat solution alloy spacer or re-bent the levers without breaking them?.

Send photos of your mystery coils collection?

Hi Bob, This was my solution re the lever position. I made a stainless spacer the required size, but obviously it has to be fitted when assembling the cable.
Brian

Bob, depends on the alloy the levers are made from? I have successfully 'bent' levers into a suitable shape with some judicious heat from the welding torch, however with a little bike as rare as yours if you wreck them it would probably be tricky to get replacements. On my Moto Guzzi Lodolo I had the same problem (do all Italians have very long fingers?) so I made a new pair from scratch cut out on the band saw from 10mm alloy plate and the hand filed to a nice profile.......took a bit of time but the end result was perfect Cheers, George