Debug this: Nearby lightning strike caused my idling motorcycle to nearly stall out.

I've got a 1979 Honda CM400T motorcycle I was riding today near a storm. I was waiting at a traffic light, and the instant a very close lightning strike occurred, my bike revved down from 1800 rpm to approx 300 rpm, which would occur if the ignition system is severely misfiring, or has no charge to ignite. The timing with the lightning strike hugely implies an electrical correlation. The system layout is that the alternator fuels both a 6-step VSI regulator to charge the battery, and a CDI ignition system in which the alternator charges a capacitor, which discharges at the correct firing angle.

My thought is that the nearby current discharge of the lightning to the ground created its perpendicular magnetic flux. This flux was powerful enough, and quickly changing enough in a single vector, to overpower the internal rotating magnetic flux of the alternator, while the power electronics operated per usual, which made the alternator create an essential DC supply on the phases due to the induced EMF, not allowing the capacitors to charge, and hence not firing the spark plugs.

But this is an oddity I've never encountered, and is particularly intriguing to me, and so if any of you have thoughts as to what happened for that second or so, I'd love to hear them.