HELP ME!!!

I'm not new here, I used to have a SN but have been away for a few years. Heres my problem:
I rebuilt and cafe'd out my 81 KZ750/4 a few months ago and it's been running great aside from a leaky overflow on the carbs that changes everytime i clean out the carbs. The BIG problem I'm having right now is that kinda randomly, the bike seems to shut off on 2 cylinders , and it seems it happens mainly the moment let off the throttle. Sometimes it comes back when the revs get high, sometimes not. If I cut the bike off and start up again, it usually runs fine again, but still does the same thing. I have no idea what it could be. Any ideas?

Check the ignition system and coils. Ran into a similar issue, ended up having a bad coil.

If you find you have a bad coil... replace both... and also look at upgrading the ignition if you haven't already. You will thank me later.... just my .02.

^ plus one! Sounds like a coil to me...can you isolate which two are cutting out? (Laser thermometer pointed at header pipes will tell you which...)

one of the coils does have a crack, I sealed with epoxy the other day but if it is the coil, it didn;t help. I do have a new dyna S ignition so maybe it's time to get the coils and upgrade the whole thing

Clear tube test and coils.
Steve

Should I attempt to epoxy the cracked coil until I can get new ones? This bike is my main mode of transportation.

No eBay APP ID and/or Cert ID defined in Kunena configurationI guess you could for whatever good it will do.
I've been looking at these. You might contact them for ones that fit your bike.

Steve

Reckon' this is the problem?

That coil is probably shot. If you cut it open, you'll probably find white crusty oxidation n stuff inside.

The coils linked above might not be a good match for electronic ignition. I think they're 4.0 ohm.
The Dyna S system may require the green Dyna 3.0 ohm coils. I'm not sure, but an alternate coil might cause the Dyna S to fail prematurely. ???

With the stock Kawasaki electronic ignition, you can use the grey Dyna 2.2 ohm or green. Since you already have the Dyna S, get the green. Also w the stock ign, you can probably use the coils from an air-cooled ZR750 (2000-04 or thereabouts). And maybe the coils from a late model Police bike. With any non-stock coils, you may have to fabricate coil mounting brackets. sometimes as simple as a couple of L-brackets from the hardware store.

I'm, a Machinist, I made the majority of the parts on the bike so brackets are not a problem

BuzyBee82 wrote: Reckon' this is the problem?

Oh, hell yes. I have a set like those. They are 4 ohm. They will work fine with the Dyna S. Dyna coils are good but for a stock bike they are overkill IMO. Expensive too. I like the type you have but they taxed my system too much. I went back to stock and they work fine. I have other things to spend $150 on. Maybe later.
Steve