possible cdi box problem

I'm new to this forum, so any info is good info. Well here is some history about my problem. I have 1981 kz1000j that last year at the middle of the summer under normal connditions it started turning the plugs black and only running on the choke. So this spring I cleaned the carbs and rebuilt them completely new kits and all and replaced the airfilters, I been throw the carbs three times rechecking. I did the upgrade with the power to the coils
with the relay. And it's still doing the same thing, only running with the choke. Sorry about the long thread but I figured all the info would be better. I was wondering if the cdi box could be doing this by miss firing or something?

The box your calling a CDI actually gives the ignition coils their ground creating the spark.I believe Kawasaki calls it a IC Igniter.

If your good a making electrical circuits of has a friend that does, One of the members here has created an substitute ignition circuit using GM ignition modules:http://www.geocities.com/loudgpz/GPZgmHEImod.html

I'm thinking of doing it if and when my IC Igniter quits on my bike.

Have you checked/replaced the sparkplug caps and sparkplug wires? They heat age and fail. Are the coils in good shape?

MFolks wrote:

The box your calling a CDI actually gives the ignition coils their ground creating the spark.I believe Kawasaki calls it a IC Igniter.

I think that's right. I believe (haven't seen the schematic) that the Kaw unit is just a solid state switch (to ground) that replaces the points, so the basic ignition function is unchanged. I think the + side of the coils go to 12V.

I have built and fixed many CDI's, they are wired differently. The +12V line does NOT go to the coil, it goes to the CDI unit. The firing line from the CDI goes to the coil's +12V terminal, but is actually hitting it with higher voltage pulses.

grizzlyadams wrote:

...1981 kz1000j...started turning the plugs black and only running on the choke...cleaned the carbs and rebuilt them completely new kits and all and replaced the airfilters, I been throw the carbs three times rechecking. I did the upgrade with the power to the coils with the relay. And it's still doing the same thing, only running with the choke... wondering if the cdi box could be doing this by miss firing or something?

If not already done, would perform compression test and also assure valve clearances being within specs.

Would also use strobe-type timing light to verify correct ignition timing and proper function of advancer.

Would also remove plugs and visually inspect spark quality.

Good Luck!

As mentioned, the Kaw ignitor is not CDI, even though many suppliers call it that. It is in fact just a transistorized replacement for points.

It may be the pickup coils. You can get them on ebay. If it truly is the IC ignitor that is bad, you can try to make one. This is the one I've been using for years. It costs about $35.

www.geocities.com/loudgpz/GPZgmHEImod.html