Homebrew ignition?
 

I've seen the open source CDI post on this site. That is more than I want to get into. I do make tube radios as a hobby so, I am no stranger to a soldering iron. For fun, I was thinking of making one of these,

http://www.floridaame.org/GalleryPag...Transistor.pdf

The only hang up is the coil. I can't find good specific information about winding one. Can I use or adapt the magneto coil off a chain saw etc? What would be the specs if I used a little choke or transformer and rewound the secondary. I was thinking a little power supply choke that put out 600V B+ and had a 6V filiment winding would step up to a bunch if used it backwards. Could I use a fly back transformer? I do not want to buy a coil, on general principle.

It seems I could make a mechanical ajustment to retard the spark for starting.

RE: Homebrew ignition?
 

The coil is a regular TCI/non-CDI automotive coil. The smaller ones available are motorcycle coils.

Good luck! ;)