I have a dual plugged BSA 441 running points and no battery. When I retarded the timing for optimum timing, I found that it was ATDC at idle or for starting, which made kickstarting difficult. I brazed up the slots in the advance unit to lessen the amount of advance (actually, in this case the amount of retard!)and it worked great. Before doing so, I asked Ed V (BSA unit singles guru) about using an ET advance unit. His advice was not to. He said that the different points cam would likely end up causing problems. I am, however, using a dual tower coil. If I am understanding correctly, I would be better off with 2 single tower coils. While my 441 fires right up and goes fine now, it would not be hard to wire up a couple of my spare Lucas coils and see if it makes a difference.
Well that would be a job for an enterprising chap, make a new ignition box for the standard Boyer with a reduced say max 4 or 5 deg retard instead of the 10 deg as supplied. Someone like DaveM could sort that i would think. And one for the standard Pazon. I believe the pickup coils are different values on each system but depending on how you approach the design this may or may not matter. In fact if you had a word with either company the chances are they would mod a pre-potted one for you anyway. (at a price) As they are analogue units the chances are it would be just a capacitor /resistor change anyway.
Wow! Thanks for all the input,some of it I don't even understand but it was fun reviewing all the responses. After talking to John Healy over the phone I decided to send my points assembly to Ed V and have him modify it to retard the advance as several have advised. I also ordered two twin tower mini 3ohm coils. I think this way the stock wiring harness will be easy to modify although I will use a tympanium regulator/rectifier. Any more imputed would be appreciated. THANKS