[wazzz]

Too bad it turns this way. I always learn from threads like this with posts from knowledgeable people.

One question though, what's the component in the CDI that produces this sound? Is it a cap or the transformer that is acting like a transducer?

I guess it is kind of accidental, as the unit wasn't designed with this sound in mind, so there might be some functioning units that produce no sound at all. That is probably what Dave/Loren means. Sound is not systematic.