TOPIC:

Trying to diagnose an intermittent issue. I thought it was carburetion, but now I'm suspecting ignition. Bike is stock, except for wiredgeorge's coil power mod. The bike runs fine out on the road, but doesn't do terribly well at idle or just off idle, which is why I thought carbs initially. At some point I noticed that 1 and 4 were not firing at idle, whereas they clearly do fire at higher rpm. I tested the coils by swapping the wires from the igniter. The problem seems to follow the wire from the igniter. Is it common for an igniter to fail in a way that is rpm-dependent? Also, I followed the two tests in the Clymer manual for testing the igniter. Failed both tests on both circuits. Has anyone here used those tests? Do they work?

Also was wondering what the secondary coil resistance should be. Clymer says 13500. I measure about 24000 on both coils, but that is through the plug caps. I dare not remove them because I don't think I would be able to get them back on.

Thanks for listening.

Check all of the connections in that circuit, clean all the connectors. Check the inside of the pickup housing for rust, etc. plus the wires. The ballast resistor can be an issue too, check it's impedance.

If the problem is following the wire then that is the route to your problem. Hard to believe the bike would run better a high engine speeds though as that is where ignition circuit problems usually get worse, check the ballast.

When you did the coil repowering mod, did you bypass the inline ballast resistor? This is the big white ceramic block mounted under the left side cover. I have found on my two shafties that resistance has crept up in the ballast resistors so much that voltage to the coils is far less than it should be. The stock coils secondary resistance has crept up in your case as well... since you have higher resistance, you will have less power I think so I suggest that when the bike is putting out less power (at idle or off idle) you will get a lot less spark and your plugs won't fire.

As far as the igniter tests specified in the manual, I have never had great luck with them working as they should. I truly believe that the best way you can spend some bucks on the shaftie is to call Z1Enterprise.com and order some green Dyna coils and a Dyna S ignition and a Dyna wire kit. Toss the ballast resistor. Also, all the fuse blocks for the shaftie that I have seen have plastic melting. It is easy to replace the fuse block with a new one from the autoparts store that uses standard automotive blade fuses.

wiredgeorge wrote:

When you did the coil repowering mod, did you bypass the inline ballast resistor?

No, I left it in the circuit. The resistance of the ballast is right on.

The stock coils secondary resistance has crept up in your case as well...

Has it? In my question I meant to imply that I was wondering if measuring through the plug caps would affect the resistance in that way. I did do a search, and there was a thread here that made me think that was a possibility. Plus, the fact that they're both the same makes me think that perhaps they're okay.

I truly believe that the best way you can spend some bucks on the shaftie is to call Z1Enterprise.com and order some green Dyna coils and a Dyna S ignition and a Dyna wire kit. Toss the ballast resistor.

I'm sure you're right, there. Problem is, I'm thinking of selling the bike so am reluctant to throw a bunch of money at it. And since it runs so well at higher rpm, I can't help thinking that most of it is okay.

Also, all the fuse blocks for the shaftie that I have seen have plastic melting. It is easy to replace the fuse block with a new one from the autoparts store that uses standard automotive blade fuses.

Thanks for the tip. I'll have a look at the fuses.

clean up all the connections and check for broken or smashed wires.. verify the simple and obvious first... just as a rule.

if the weak spark side goes from 1 side to the other side with the igniter lead first I'd check the air gap between the crank advancer/reluctor and the signal generator pick up coil unit under the right engine cover .015~.018 inch not over.020 and make both sides air gap the same if they are different.
clean the metal pick up pieces and pointer tip both.
of course check all the ignition wires

the plug caps are often a problem source for low rev ignition loss, but the cold cylinder won't change. I like to cut a .250 inch piece of plug wire off and reattach a tested known good cap back on if there is enough length.

I've seen these ignition boxes go half bad.. but not often because when they go bad usually it is the whole thing kapow! no spark at all

good luck.

Post edited by: trippivot, at: 2008/01/02 15:34

wiredgeorge wrote:

... order some green Dyna coils and a Dyna S ignition and a Dyna wire kit.

Just to be sure ... the dyna-s is self-contained? No external igniter?

The Dyna S essentially doesn't use a stand alone igniter box... what look like pickup coils are the whole deal; signal from the pickup coil goes direct to the ignition coil. They are real cheap at www.z1enterprises.com.

Just a quick follow-up. Thanks for all the suggestions and info, by the way.

I used some De-Oxit on the connectors and the problem disappeared. Whoever said to check the simple stuff first was dead on. Of course that doesn't mean that it probably wouldn't run a bit better with a Dyna-S. Runs great now though, so I'm thinking I'll sell her. Anyone interested in a clean low mileage 1980 kz1000e? I guess I'll post it in the classifieds.