How to troubleshoot CDI/Magneto when no spark

Hello all!

This is my first post. I picked up a used motor/bike at a sale this weekend (a King's Motor Bike Kit 80cc? I think), and it was in need of some serious TLC. However, for $15 I wasn't going to pass it up. I've mounted everything properly (which it wasn't before) and took it out for a spin. No spark.

I started at the beginning, taping my volt meter to the lines coming out of the magneto and went for a ride, and got a wide range of voltages (usually 3-4, only occasionally higher. I don't know if that is right. Seemed low, but I'm new to this engine. Additionally, the PO had lost the plug wire, so I bought a standard auto one and a like spark plug. Could my CDI be dead? Does anyone know a good way to check a CDI (ohms metering or something?).

Here's some pics of the new toy! Picasa Web Albums - cory - Chinese Motor...

Thanks for the follow up. Here's the answers:

I had the volt meter set in the 20V range. I was *mistakenly* thinking I was looking for 12V.

Let me adjust the gap when I get home and see. I didn't have a gap spec, but I couldn't get either the old or the new plug to spark. I am also not familiar with a spark tester. Would you suggest the easiest way is to just touch the side of the plug to an exposed part of the frame while cranking?

Can I put my meter on the output side of the CDI and expect to see anything? Do you know the Volt range I might see?

Thanks for the next steps. I hate when I want to troubleshoot but can't think where to go next.

Excellent. I'm so glad you sent me back to double check. I'm used to a much higher voltage system, so I wasn't looking close enough. Turned out the light in my garage though, and there was consistent spark.

Now all I have to do is get the thing to start. I think it got pretty flooded, so I'm going to clean it out, and get some good, fresh gas in the tank. More updates pending...

Thanks again!