I KEEP BLOWING THE 2-3 COIL ....ARRGG!!

Ok - she's a 1978 KZ650 Custom with Dyna Electronic Ignition and Dyna coils. Ran great with no issues until last fall when the 2-3 coil blew and she would run only on the 1-4 cylinders. I replaced the coil with a spare I had and at first I thought all four cylinders were firing, but as I hit the road, it was clear 2-3 still would not fire. I then installed a new set of Dyna coils and replaced the plugs and wires. She fired right up and all four cylinders were firing as all four exhaust headers were hot. Then as I'm looking at the 2-3 coil I see a spark and hear a spit from the coil. The bike stays running, but gets rough, and the 2-3 header pipes cool to the point I can keep my hands on them.

Does anyone have any suggestions as to what is causing this?

Thanks


Mike

i had an issue with one coil going out and for me it was becuase i had the wrong ohm coil....i am not so good at explaining electrics and can barely fix my own bikes elec so it is hard to give the right words to it....but my problem was always with the same coil and showed up after a while i would replace that coil which looked fine ,with a new coil and it would fail again...i threaded here and the answers i got were that my dyna ignition required 3 ohm coils......i bought a set of 3.ohm green dyna coils new/used off e-bay for 60 (after many outbids on used ones) and installed and have never had the coil issue again 2000 miles ,where before they burned out at 150-300 miles....could it be that your coils are not the right ohm rating for your model ignition set up........good luck craig......p.s i googled dyna and they have phone tech guys to answer questions if you have your ignition #s they might trouble shoot with you.......peace

Craig, thanks for the quick reply. I have the Dyna green 3.0 dual output, which is correct for the bike. I should have stated that in the orginal post.

Out of curiosity.....

Which plug wires are you using (resistive/non-resistive)?

Which plugs (resistive/non-resistive)?

Ignition Timing (static & running) correct to spec?

OMR

If not already done, would check charging system by measuring voltage across battery terminals at 4000 rpm. Higher than 14.5 volts casts suspicion on voltage regulator.

Am uncertain about whether charging voltage higher than spec may burn out a good correct ohm coil, so just guessing until better more competant advice arrives.

Good Luck!

MentalMike wrote:

Ok - she's a 1978 KZ650 Custom with Dyna Electronic Ignition and Dyna coils. Ran great with no issues until last fall when the 2-3 coil blew and she would run only on the 1-4 cylinders. I replaced the coil with a spare I had and at first I thought all four cylinders were firing, but as I hit the road, it was clear 2-3 still would not fire. I then installed a new set of Dyna coils and replaced the plugs and wires. She fired right up and all four cylinders were firing as all four exhaust headers were hot. Then as I'm looking at the 2-3 coil I see a spark and hear a spit from the coil. The bike stays running, but gets rough, and the 2-3 header pipes cool to the point I can keep my hands on them.

Does anyone have any suggestions as to what is causing this?

Thanks


Mike

Make sure your alternator output is giving the correct system voltage (about 14V when running). Also make sure your battery is good, it filters out the pulses coming from the alternator and a flaky battery will send high voltage pops onto the electrical system. The other thing may be voltage spikes at or near the electronic ignitions power feed source.

Patton wrote:

If not already done, would check charging system by measuring voltage across battery terminals at 4000 rpm. Higher than 14.5 volts casts suspicion on voltage regulator.

Am uncertain about whether charging voltage higher than spec may burn out a good correct ohm coil, so just guessing until better more competant advice arrives.

It can because it will give the elctronic ignition a higher working voltage that it uses to "light up" the coil's primary side and that will cause higher voltage stress on the coil.

Thanks for the responses fellas. I can do most of the work on my bikes, but I'll admit, the electrics are my weak point.

I will troubleshoot further with the posted suggestions and I'll let you know how I make out.

check your electronic ignition/points,i would think a charging problem would affect both coils