Found this amongst all the rubbish on my work bench the other day. It's one of the original coils from my 1100Sport based project (the Single seater)
When I was sorting out the wiring I thought I was being very clever leaving on the original coils. I had replaced the 1100motor with a Spada III item using points and condensers. A few weeks previous to the day of the bang I thought one coil in particular seemed to be getting hot very quickly along with some crackling noises. It was one hell of a bang as you can probably gather from the photo.
A lesson learnt anyway that you can't mix the later type coils with early points ignition.