Dyna s coil discharging when key is on/off

I have a 1976 KZ 900 LTD that I bought not running with the 1/4 coil burned up. I replaced the ignition system with a Dyna S system with the green coils and matching plug wires. The bike runs but after shutting it off and turning it on again coil 1/4 throws a spark. I could hear the coil clicking and pulled plug#1 and it sparked. I reversed the leads to coil 1/4 and now plug#4 sparks. The battery is new and I cleaned the grounds to the coils. Both the key switch and the run switch will cause it to spark. I hate electrical problems!! Possible voltage regulator?

That's normal. You don't want to leave the key on or you can fry another coil.
Steve

They all do that.
Depending on where the crank stops the magnet on the rotor may come to rest close to one of the triggers and the pulse caused when the ign is turned on and off will induce a spark.
1 and 4 are on the same coil so both will spark at the same time .
The same goes for 2 and 3.

I turned the motor over so that wouldn't happen and it still does it. And only 1 plug wire sparks, you would think that both 1/4 wires would spark but only the 1 does. And this is normal? Would this also explain the small pop out the exhaust after running it and starting it again right away? I'm thinking that spark is igniting whatever fuel is left in the cylinder.

It happens on my bike sometimes. Good thing it doesn't have a long stroke like a HD. It'd walk away from me. :lol: How does it run otherwise. Pics?
Steve

It runs o/k but I have not run it long. Just did a complete rebuild from the bare frame. Need to synch the carbs and sort things out. Been apart for 2 years and hopefully next weekend I will be done. Thanks for all the help! I will post pictures soon.

You may only get one plug to spark just by flicking the ignition due to that lead and plug having a fraction less resistance to the other .
Electricity will favour the path of least resistance so it will all depend on the quality of the plugs earth contact at that particular time etc.
Many times I have fired a cylinder with a Dyna as a party trick just by flicking the kill switch and produced either a carb backfire or flame from the exhaust and once the bike actually started which was impressive but I have never been able to repeat.