nice to see this project is going somewhere.

i've made a few ignitions similar to the one posted by JMJ a couple of years back with good success but winding tiny toroids is no fun at all...and i doubt hacking little E-cores would be much more fun either. a while back i got some of these [link=http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=3851&Site=US&Cat=35062915]transformers[/link] from digikey and hope to try them out soon.

spark coils for CDI don't need insulation between layers if done right. the secondary winding is 5 or 6 narrow coils stacked on the bobbin (made from plastic washers glued to a plastic tube) and the primary is 30 or so turns directly on a ferrite rod and placed inside the bobbin. this is the same as the trigger coils used in strobes, camera flashes and the tiny coils found on zenoah engines. works good, easy to do and best of all they come out small and light.



good luck,
dave