Jarco :
Its been done before but cant help you more then give you this link:

http://www.vespa-ciao.nl/forums.php?m=posts&q=9539

Hope its usefull.

Close but no cigarr, my friend.

The link is for contact points ignition.
I need to find a way to solv this for CDI´s.

bentwi :
Can;t you just put the battery on the CDI and connect the wires right?
won’t that work?

No it won´t.
You know that there are a small picup coil inside the flywheel that gives the CDI unit the signal to send the spark to the plug.

Without that coil no spark will be sent, the CDI will not know when to send the spark.

I will figure how to get this ignition point to work, I would also like to make this ignition point adjustable.

Martino :
It ain’t all that easy. Look at the first post. “pickup”

I don´t follow you here, can you please help me understand what you mean?

I need some guidance from you skilled guys.
By looking at this chart I believe that the green cable is a + cord that feeds the ignition coil/CDI, number 7.

The red cable is coming from the pickup coil that is sending the signal to release the spark.
By looking at the chart the red cable is also a a live cable fed with a + currency.

Does anyone know if the coils are producing AC or DC?

The white cable could be a minus lead but the CDI unit is grounded separately.

Does anyone of you know for shure the coil deliveries?

ArvidW :
Why use a CDI ?

Get standard contact breaker points, a battery pack, a standard capacitor and you can ditch the flywheel.
Works perfectly on a 50cc engine.

Yes, great idea but I prefer to go without breaker points and find a solution with a Hall trigger to send the ignition point to the coil.

How was the engine caracter? Was it nervous or had poor idling?
Did you feel any power gains from running with no flywheel?

More to consider or is it just a straight mod?

I don´t need to power the lights so that is really out of the question.

ArvidW :
Power didn’t rise, acceleration from standing start improved drastically in the period when the clutch was slipping. Wheely from standing start was easy. At speed it did behave just like with flywheel except for the throttle response.

Idle was worse than before, it had to idle at a high rpm to keep running.

It was one of the simplest mods i’ve ever done. You can build it with all stock parts except for the battery pack. Cooling was not a problem because I had a custom completely open subframe so the cylinder was exposed to sufficient airflow.

The coil I used used approximately 5 Amps so a small 6cell RC car battery pack (7.2v 3Ah) is empty in approximately 30minutes.

I will explore this one as I am building my short track sprint racer.
I will use my CDI carter and will find a way to replace the breakers.

Thanks for this idea.