KZ400 Coil problems.

Ok ladies and gentlemen I have a KZ400 that I am restoring and I am trying to figure out what is wrong with the ignition circuit. I replaced the condensor and points timed it out and everything worked fine. I statrted the bike and warmed it up to set the carbs which I just rebuilt and it ran for about 5-6 minutes. Suddenly it shut off, and not like the stuttering shut down of carb problems it was very sudden. So I pulled the plugs to check for spark and ther was nothing. I took out the old multimeter and read 9.6 volts going to the coil (ya I know the coil power mod is the next thing on the list for this I just wanna make sure it works first). I switched to ohms and got only 1.4 ohms across the coil. I never checked this before I started it but isn't supposed to be more like 4 ohms? Nyway if anyone can enlighten me on what is going on that would be great.

Becker wrote:

Ok ladies and gentlemen I have a KZ400 that I am restoring and I am trying to figure out what is wrong with the ignition circuit. I replaced the condensor and points timed it out and everything worked fine. I statrted the bike and warmed it up to set the carbs which I just rebuilt and it ran for about 5-6 minutes. Suddenly it shut off, and not like the stuttering shut down of carb problems it was very sudden. So I pulled the plugs to check for spark and ther was nothing. I took out the old multimeter and read 9.6 volts going to the coil (ya I know the coil power mod is the next thing on the list for this I just wanna make sure it works first). I switched to ohms and got only 1.4 ohms across the coil. I never checked this before I started it but isn't supposed to be more like 4 ohms? Nyway if anyone can enlighten me on what is going on that would be great.

Is this the stock coil? If it is, I do think it's hosed.

I have the 750 twin, and probably a similar coil. I think the stock coil resistance should be more like 4 Ohms than 1.4 Ohms. That is the lowest I ever heard of, since it would allow about 10A of current flow through the coil primary when the points close. That would dissipate 140 Watts in the coil and fry it quickly.

Just to help you out, I'll show you a site where they sell NEWreplacement coils for the twins for $49:

www.regulatorrectifier.com/catalog/kawas...ion-coil-p-1628.html

I paid about $30 + shipping for a greasy used one I found on Fleabay because I didn't know about this place selling new ones so cheap.

Thanks for the help. I have to agree I think that this one is grenaded but I just bought another one from that website so I'm excited about that. I'll let you know how it all turns out. Thanks again.

1.4 ohms isn't so far off if the bike also ran a ballast resistor. I checked at Kawasaki but the parts diagrams are tough to navigate and seemed incomplete. Do you have a wiring diagram?

KZCSI

KZCSI wrote:

1.4 ohms isn't so far off if the bike also ran a ballast resistor. I checked at Kawasaki but the parts diagrams are tough to navigate and seemed incomplete. Do you have a wiring diagram?

KZCSI

I have the wiring diagrams. What should I be looking for that would be a ballast resistor? Better yet what is a ballast resistor?? I already bought a new coil but I would like to know what a ballast resistor is. Thanks for all of your help.

Becker wrote:

KZCSI wrote:

1.4 ohms isn't so far off if the bike also ran a ballast resistor. I checked at Kawasaki but the parts diagrams are tough to navigate and seemed incomplete. Do you have a wiring diagram?

KZCSI

I have the wiring diagrams. What should I be looking for that would be a ballast resistor? Better yet what is a ballast resistor?? I already bought a new coil but I would like to know what a ballast resistor is. Thanks for all of your help.

A ballast resistor is an external series resitor that was wired in line with some coils once upon a time. It's job was to limit the DC current flow into the coil primary when the points closed. I remember back in 1979 asking the dealer about my 750 twin, and he said Kawi only uses 12V coils (so there would be no external resistor).

If there was one, it would probably be a small block maybe one or two inches long mounted to the frame somewhere. They get very hot so they need heat transfer. If your bike is stock, it won't have one.

Post edited by: bountyhunter, at: 2008/03/05 13:00