possible blown coil again???!!!!!

Anyone have an idea why I might have blown a coil (1/4) for the second time? I have a '77 kz650C1 with dyna s and the coil mod. That all ran great for about 2 yrs then I blew a coil, replaced it, seemed to be good and now that im trying to get ready for the new season im getting no spark on 1 or 4 again. Im not positive its blown but im not sure what else could've gone out that would only affect one coil. Any help would be greatly appreciated.

Are you sure its not the dyna s
Mine went bad it was tricky trouble shooting it though because it would work periodically. work one hour and then wouldn't work for a day. try switching the main coil wires around ( not plug wires). and see if 2 and 3 stop foreign..

If you have the old coil test it with an ohm meter.take it to Autozone if you dont have a meter.I do all this with my phone and I'm not computer savvy the guys like Patton and its 650ed have sent me instructions on how to do the test try a search.or I'm sure they will read here and chin in.they got me up and running

WTF...people are still doing that stupid coil mod :blink:

Is there a reason why you wouldn't want to do it? I thought the purpose of the coil relay mod was to get full battery voltage to the coils?

drfantastik wrote: Anyone have an idea why I might have blown a coil (1/4) for the second time? I have a '77 kz650C1 with dyna s and the coil mod. That all ran great for about 2 yrs then I blew a coil, replaced it, seemed to be good and now that im trying to get ready for the new season im getting no spark on 1 or 4 again. Im not positive its blown but im not sure what else could've gone out that would only affect one coil. Any help would be greatly appreciated.

Besides a mal-functioning ignition coil, there are several other possible causes for lack of spark on #1 and #4 plugs.

Would begin the diagnosis by using a volt-meter to confirm existence of full battery+ voltage at the dual connector (shown below) with the ignition switch ON.





Good Fortune!

drfantastik wrote: Anyone have an idea why I might have blown a coil (1/4) for the second time? I have a '77 kz650C1 with dyna s and the coil mod. That all ran great for about 2 yrs then I blew a coil, replaced it, seemed to be good and now that im trying to get ready for the new season im getting no spark on 1 or 4 again. Im not positive its blown but im not sure what else could've gone out that would only affect one coil. Any help would be greatly appreciated.

Couldn't count how many threads I have seen where one side of a Dyna blew out. Try switching the coils and see if the spark follows the coil or stays on the same side.

martin_csr wrote: Is there a reason why you wouldn't want to do it? I thought the purpose of the coil relay mod was to get full battery voltage to the coils?

Some of us think it's a solution in search of a problem. If the voltage is low at the coil, the problem is a bad ignition switch, fuse connection, harness connection, etc.

In my life I have replaced so many blown or seized relays, I refuse to put them in line with any device I really want to keep working.... especially if there is no compelling reason to.

First thanks for the responses. So... I have ruled out the coil and I have good voltage to both coils. When I switched the wires on the coils I got the other coil to spark on 1 and 4. So im fairly sure that one side [1/4] of the dyna went bad. So unless someone thinks it may be something else, im going to have to replace it

drfantastik wrote: First thanks for the responses. So... I have ruled out the coil and I have good voltage to both coils. When I switched the wires on the coils I got the other coil to spark on 1 and 4. So im fairly sure that one side [1/4] of the dyna went bad. So unless someone thinks it may be something else, im going to have to replace it

Add this to the "dead Dyna" pile.

From what I read, the factory Kawi electronic ignitions are more durable if you can get one.

Ok, so next question. Could a problem with the regulator/rectifier have blown the module or would it most likely have been an isolated problem? Just wondering, if I replace the module will this be the end or should I look at replacing the regulator/rectifier as well

drfantastik wrote: Ok, so next question. Could a problem with the regulator/rectifier have blown the module or would it most likely have been an isolated problem? Just wondering, if I replace the module will this be the end or should I look at replacing the regulator/rectifier as well

Depends on the circuitry. Excessive system voltage may very well have killed it..... killed my CDI one time.