Dyna S constantly sparking a problem or not?

I finally got the parts together to put my 1978 KZ650C back together. I got the top end together and the carbs and coils installed so I could see if it ran before putting the exhaust on. I turned the key and I can here a buzzing noise comming from the cylinders and it sounds like it's constantly sparking. Is this normal? when I turn it over I can here it come on and off again. I think it is probably just the ignition sitting on the open position when I stop. Also when I'm kicking it every once in a while when kicking it'll stop instantly... kinda like it has too much compression. Any replies are greatly appreciated.

Thank you

jordan172005 wrote:

I finally got the parts together to put my 1978 KZ650C back together. I got the top end together and the carbs and coils installed so I could see if it ran before putting the exhaust on.

I thought it was unsafe to run with no headers on. maybe I'm wrong, I thought you could warp an exhaust valve that way.

jordan172005 wrote:

I turned the key and I can here a buzzing noise comming from the cylinders and it sounds like it's constantly sparking. Is this normal?

I don't think so. It should only spark when the points go from closed to open.

If it is an electronic ignition like mine, it may have an internal DC-DC converter to boost the voltage which will make a buzzing whine noise anytime the key is on. My CDI does that.

jordan172005 wrote:

Also when I'm kicking it every once in a while when kicking it'll stop instantly... kinda like it has too much compression. Any replies are greatly appreciated.

Thank you

After I rebuilt my twin the compression went up to 165. I couldn't kick that much over with a rented leg.

Well the sound is coming from the top end though not the ignition thats why I think it's the plugs sparking.

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Ok, I'll check the plugs tomorrow and I'll try again.

I recall someone else having this problem. It's certainly not normal and may be defective (if it's indeed sparking constantly).

It can also be caused by pulsing power to the Dyna S. This may happen if you have a battery charger connected to the bike.

The Dyna S is a Hall-effect triggered, transistorized (or IGBT?) Kettering ignition (I never measured any DC step-up on the output). This means when the ignition is on, at least one coil, but usually both, are getting full primary current until the crank moves. (This will heat the coils pretty quickly, so don't leave the ignition on without running for long periods.)

If you are near a magnetic source, like a big AC transformer, that may also cause the repeated arcing.

I did have a big battery charger on it cause my battery was dead. How am I supposed to start it if I can't have a battery charger on it?

If the battery is simply discharged, you can charge the battery with the ignition turned off. If the battery won't take a charge, then you'll need to get a new battery.

You never want to run the bike with a working charger connected (or jumpered to a running car). It's ok to run it off a car battery if the car is not turned on.