Home made CDI ignition

[dz99]

Hello!

Is anybodey has built CDI unit for 2T bikes? Transistor, thyristor, FET, etc. type's are welcome!
CDI means - Capacitor Discharge Unit

Any kind of schematics PCBs are welcome! ,

https://en.wikipedia.org/wiki/Capacitor_discharge_ignition

I will use it in my Simson, S50B. Not familiar? Never mind!
https://en.wikipedia.org/wiki/Simson

[hmmmnz]

hey there, sounds like a good mission,
but why not just get a cdi from a different bike, since they all seem to work the same,
and just come up with some sort of trigger from your original points system.. a magnetic pick up mabee,
might save you a bit of work and itll already have all the cooling fins ect on the casing.
good luck
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[finpos]

I think I can see what you are trying to do!

If you search around an the internet you can find schematics for CDI ignition. But they are difficult to build reliably, because the electrical system on a bike is really noisy, and you end up blowing components on a fairly regular basis.

If you would want CDI, you can buy a fairly cheap one of a vespa or lambretta parts dealer. This is the type that has a built-in coil. These do not have an ignition advance in them, so your thingy will only rev to about 4-5000 rpm, which I very much suspect is how it worked originally from it's points ignition. If you do need to advance the ignition, the job will be much harder because you will have to find a CDI unit which has an advance curve built into it that will match the (presumably mechanical) advance already present on the bike. That might involve a lot of trial-and-error

The biggest problem you will have is to arrange some kind of pick-up mechanism on th flywheel to use in conjunction with the CDI. The normal method of conversion is to use a special stator coil which has a pick-up built into it. But I don't think you'll find one for your type of engine.

Your alternative is to go for something called "Transistor assisted ignition" which uses your original coil , points and advance mechanism, but doesn't put a high voltage on the points (so they last forever) and gives much cleaner switching on the low tension side of the coil (so you get a better spark). You can even buy kits to make your own

edit - TAI kit here: https://www.maplin.co.uk/Search.aspx?criteria=VE00A&C=SEO&U=Strat10&doy=search
finpos.