The only thing I can think of is maybe a stock spark plug cap.
I think I killed mine by unhooking the spark plug wire, and turning the motor over to check the compression. I forgot to hold the kill button down. They say that can damage a cdi.
The stock spark plug caps are crappy enough to do the same thing maybe. Does your ever come loose from the spark plug?
I was really wobbly...It didn't come with the rubber boot and I didn't think of taking it off of the old one. But yeah I could have easily done that, because I didn't know that was bad.