TOPIC:

I'm going to try using the Kawi electronic Ign. on my kz650 again. Which coils?

Either using the kz1000 pick ups from my original conversion, or the GPZ750 pick ups I scored recently.

I had some problems the first time around, and thought it was IC Igniter related. Found another IC Igniter, but giving it a quick try at the start of the season didn't work right off.

Now I'm wondering if the stock kz650 coils could be part of the problem. My Clymer and FSM manuals state the "value should be 4.0 ohms" for the primary resistance.

I will be using the GPZ750's elec. Ign.'s backing plate as it's a dirrect fit to the 650.
What's the coil's primary resistance in a Kawi electronic ignition system?

Just looking in the manual again, the 1981 650, which uses electronic Ign, states the primary resistance value should be 1.8-2.7 ohms.
Is this why I'm having problems using 4.0 ohm coils?

What exactly are your symptoms?

First time around, my bike was only running on two cylinders, then kicked in on all 4.
After a few rides I couldn't get her to run at all. Did some checks and found the IC Igniter's red wire on one side was not testing properly.

Found another IC Igniter a few months later, and tried the switch from points to electronic Ign. again.
Hooked it all up and she wouldn't start.

I didn't try trouble shooting it at the time. I just unpluged it all and went back to the points and she fired right up. I made everything plug and play with a spare harness, so the swap back and forth is easy.

After reading the coil post by Bicycle Lee, I got to thinking maybe the coil resistance may be a contributing facter in my troubles.

Kawasaki used two different systems. some were 3.0 Ohm systems and some were 2.2 Ohm systems. First you must find out which ignition you have and than match the coils to it. There was no 4 Ohm system of which I am aware. The erly points ignition used a 1.3 Ohm coil with a 1.7 Ohm balast resistor to bring it to 3.0 Ohms. This than carried over to the first IC ignition systems which went to 2.2 Ohms and had matching coils dropping the resistor from the circuit. Forget the Clymer mannual and get a real Kawasaki manual. It is worth the Investment. You will know what I mean when you get your hands on one.

All of the KZ points coils I've dealt with were around 4 ohms. All of the electronic ignition coils I've dealt with were around 2.2 to 2.6 ohms.

I don't think using the 4-ohm coils would be a problem on the electronic ignition, except at higher RPMs. The issue is dwell. The points use a fixed 180 deg dwell angle. The electronic ignition uses a variable dwell angle, but it does not vary by much. It has about 100 deg at idle and goes to about 120 deg as the RPMs increase. At lower RPMs, there is no issue since the dwell time is plenty long enough for the coils to go into saturation. At higher RPMs, the dwell time drops off (even though the angle increases slightly). At 120 deg, it has 30% less charge time than the points ignition. This probably only becomes an issue above 5000 or 7000 RPM. This means it needs a hotter coil which charges faster, which is why the 2.4-ohm coil is needed.

If you are missing at lower RPMs, it may simply be the coils are shot. You really don't want to be riding on 25+ year old coils anyway. One hard rain can leave you stranded. I would start with new coils. 3-ohm coils from Accel or Dyna work fine with the electronic ignition.

The one great thing about the 4cyl Kaw system is that you can troubleshoot the whole thing one part at a time by swapping wires and a few other tricks. The pickups, ignitor, and coils can be ruled out, one at a time, as long as you can determine which cylinders are not sparking.

RE: gpz750 pickup coils. If they are the later type, from an electronic-advance unit, I don't think they will work. If the actual pickups look just like your old pickups, it should work.

Post edited by: loudhvx, at: 2007/11/11 12:30