My k2f with an old plug. This is what powers our bikes!
See the blueish flat 'cloud' that always appear? It forms on the inner electrode on one mag firing side, and outer electrode on the other side (see the pic
here) probably sign of an inverting L\R polarity of the ht supplied by the mag.
As an anecdote, my canon slr went nuts when held close to the running magneto, locking up with all kinds of error messages onscreen. And surely, I am too close to the mag as well...