fried dyna s???

Recently acquired a 1976 kz900. The wires to the kill switch and start button had been ripped out of the handle. Found the wires to get it to turn over. But was not getting any fire. Got the coils wired up. While I was testing each coil I touched the pickup lead on the coil with the ground by mistake. This caused the fuse to blow. Put new fuse in and tried to start..only getting spark on cylinders 1@4 .if I reverse the leads going to the coils I'm only getting spark on cylinders2@3. Is that side of my dyna s fried from being shorted to grounded out. How can I test it.

Could be fried, Dynas are known for blowing up on a regular basis. Shorting the Dyna's coil drive output terminal to ground could blow it.

Test it?

I would swap the known good pickup and known good coil to each side of the Dyna in turn and see if the spark goes with them or not.

bountyhunter wrote: Could be fried, Dynas are known for blowing up on a regular basis.

Where do you get that info from? Been running a Dyna S in my 650 for about 20 years now. Every older bike I own has a Dyna S and I have never had any issues with them.
Could be the 2+3 coil bad also try switching coils and see what happens.

As known, the 1&4 coil primary winding grounds and ungrounds through a black wire connected to the left Dyna-S module. And the 2&3 coil primary winding grounds and ungrounds through a green wire connected to the right Dyna-S module.

Perhaps there's an internal break or fray in the green wire from the right Dyna-S module.

As left module to left coil will produce spark on outside plugs 1&4, could test whether right module to left coil will also produce spark on outside plugs 1&4.



Good Fortune!

baldy110 wrote:

bountyhunter wrote: Could be fried, Dynas are known for blowing up on a regular basis.

Where do you get that info from?

This forum and others. I could count the number of stock Kawi electronic ignition units that have failed on about zero fingers.

I have seen a couple of dozen posts about Dynas where one drive output (side) is dead. Maybe from "improper use" (shorting accidentally) but they do not appear to have any kind of internal protection that works very well.

Problem is coils fail with time, and if the electronics driving the coil primary is not robust enough to limit current/power internally, an arcing coil will take the ignition drivers out.

I have never had a Dyna unit to fail on me but have bought a lot of used ones that had one side bad.

I do know a Dyna can fry with a voltage spike if the regulator goes bad.

Perform the Dyna-S Static test....

Follow this link in case you need....
Dyna-S Static Testing