coil burning out

since having the bike it has eaten 3 coils only had it 6 months
both the stock aftermarket ones and one gen yamaha one, fitted the yam ones when it aet the stock ones and all i had in the spares pile was a pair of fz750 coils.
what could be cuaseing the coils to go? have checked the charging system and am getting a consant 13.2v to the coils with no spikes, have good earths on them and the wires are soldered and heat shrinked so no damp can get in.
bike is my daily so need to get this sorted.
thinking about getting the whole dyna set up but really dont want to cook that as well.
cheers rob

search the archive under burning up coils and you may get some help from an old thread i had for a kz900...my problem was a dyna ignition eating the stock and e-bay cop bike coils...that came on the bike..it got where i would get like 300---then 50 miles out of the replacement stcokers of e-bay.......i finally got dyna(green)3 ohm coils new from a guy on e-bay fairly cheap(he never installed em)...some messing around calls to dyna for wire advice and with new auto zone plug wires they have been my answer a couple thousand miles so far and no more parking and calling for a ride....thats my story...i also did not want to burn an expensive set,,,,but it worked putting dyna coils..after i gave up and took the chance.....good luck

If you're running the stock points system, get some 4-5 ohm coils, that ought to solve your problem.

For those not in the know, good earth means good ground

Now, exactly what has a "good earth"? Not the coils I hope, they only ground through the points (or igniter if electronic ignition).

Measure the primary resistance (two small posts or wires) on your coils, 3 ohms or less is for electronic ignitions, 3 ohms or more is for points. Put 2 ohm coils on points without resisters and they won't last long.

yeah think this might be part of the problem the fz750 has electronic ignition so the coils would not off been to spec for points.
so do i now go for the hole hog and get the dyna stuff all through or just replace the coils and carry on?
see my engine post for other ideas

i'm shitty on reading elec readings but you are prob just having the wrong coil for your application and once solved would not have to change anything more at the moment and can have transpo
STEELL is right for sure about the resistors imo and you gotta check all his tips...my coils getting right was so easy once i followed the advice spec for my prob and doneeeeeeeee...good luck

steell wrote:

Now, exactly what has a "good earth"?

Pearl S Buck if my memory serves me.

Couldn't resist.

I agree get the stock four Ohm coils and they should work fine. Or, stick a one Ohm power resistor in series with the 2 or 3 Ohm coils and that should help them survive, but that wastes ignition energy. better to use a four Ohm coil.

Z1 sells the stock replacement coils at a very low price.

bountyhunter wrote:

steell wrote:

Now, exactly what has a "good earth"?

Pearl S Buck if my memory serves me.

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