1980 KZ750E Ignition problems

Hello, My name is Dane and I am new to this group and to bikes in general. I picked up a kz750 a while back and have had continuous probs with it. As I found and repaired one prob, another would appear. The current problem I'm having is that I have no spark on cylinders 1 and 4. I have changed spark plug wires, plugs, and replaced the suppression caps on the wires. I think I have it narrowed down the the igniter but am not certain. I have switched coils to see if one was bad. The spark did not follow the coil, so I believe they are both good. Next was the pick up coils. I ohmed them out and got bad readings. So I changed them with another set. I thought the igniter was questionable then so I went ahead and ohmed it out as well. It read open on 2 legs and high on the 3rd. I got another one from a 650 from the person I got the bike from and tried it. Nothing changed. I ohmed it out and it also had 2 open legs and the 3rd was way over specs. I picked up the modules and various other things required for Lou's hei replacement system but I want to ensure I'm on the right track before I start the process. Basically, is there anything I might have miised?

I think you're on the right track. I have a Dyna S and am happy with it. I still carry my points plate and cam just in case. If I break down, I'm back on the road in 15 minutes.
Steve

IC ignitors usually fail on one 'side' , the meter truth table in the manual is a rough diagnostic, i think the only sure fire way to test them is to fit it on the bike. I had one fail - it was only on one side.

If you turn ignition on, and sweep past the pick up with something metallic it will trick the IC Ignitor into firing. Alternatively you can use a multimeter set on Ohms to do it from the IC block connector, probing the two relevant terminals that would corrspond to the pick ups.

I did not try the trick with the pick up coil but I did do the other troubleshooting tips in the manual. I didn't have access to a manual for a 750 specifically. Rather one for a 1000 and another for a 650. But the info was the same. The bike will run on two cylinders where the 2 that are working are cylinders 2 and 3. I was testing voltages to the coils and found an interesting anomoly. I got battery voltage when testing the red wires on both coils. I also got battery voltage on the green wire for the left coil. Here's the odd part. I got inconsistent voltage on the black wire for the right coil. It ranged from battery voltage all the way down to .77 volts. That's the coil that goes to the cylinders that are operational. Now it only fluctuated with the bike running. Is this normal or could this be a byproduct of the faulty igniter?

I think you're on the right track also. You can download the 750 manual here kz.bike-night.com/manual.html

that's a good tip from Tyrell Corp

you can only really test voltage at the coils when the engine is not running. When engine is running voltage to the coils is on off on off so essentially could be all over the place. Not a good test when engine running

Thanks for the link. Where is the best place to mount Lou's module set up to the 750e? I'm thinking behind the plastic cover over the rear brake reservoir but can't find anything to bolt it to. The other place I was thinking was where the factory igniter is bolted but idk if there's enough room. Any suggestions?

Problem is fixed!!! Found a bad pick up coil in the process of troubleshooting the igniter issue. Changed them out, wired Lou's prototype in the original configuration and the bike runs great. Thanks for the help!

I was wrong. Only temporarily fixed. Since my last post, the starter button has quit working but I'm thinking that's a separate issue. Jump the solenoid, it turns over but I loose 2 cylinders at idle. At higher rpms they come back. It did this before when it lost the 2 cylinders completely. It was gradual, like this time. I'm at a loss as to what's going on. Help please.