TOPIC:

Most Kz's do not use a ballast. The ones that do, don't use them the same way a car does... similar but with some subtle differences.

A car uses a ballast resistor that changes resistance with heat. This is because at idle, the dwell time gets long and the coil gets hot. To counter this, the ballast resistor gets hot and increases resistance to reduce the current in the coil. This is the average current.

In the Kz's that had ballast resistors, the resistor was pretty much just a simple, big resistor with relatively constant resistance. This was for the earliest electronic ignitions in Kz's. The coils supplied were too low in resistance and probably would stress the igniter too much. The igniter could handle coils that were 2.3 ohms, but apparently Kawasaki could only get 1.5 ohm coils. So they used a resistor to make up the difference.

They needed "faster" coils (coils that charge faster are usually lower in resistance) because the electronic ignition used a shorter dwell than the points ignitions which used 4 ohm coils. The shorter dwell, I believe was to counter the effects of crosstalk in the two ignition signals. It greatly reduces the crosstalk without having to use any extra components unlike the Honda electronic ignitions.

A year or so later, Kz's came out with the normal 2.3 ohm coils for electronic ignitions and did away with the ballasts.

I was revving the bike at a stop light the other week only to have it fall back to idle and shut off...So naturally I got it onto the sidewalk of a very busy intersection and started to pour sweat while doing what most uneducated drivers might see as someone hoping up and down on their motorcycle for no apparent reason.

As far as Im concerned, the points have always been the problem and although my friends datsun pickup runs great with points, I dont care for beating a dead horse trying to get the points to work even if other people know how to beat it the right way .

Seeing as how the condenser was new, is there any other reason on this earth why fat sparks would go across the points??

Spring on the points could be crooked or points badly pitted.
Steve

If you rotate the crank to a position so the points are closed, you should be able to check for spark just by opening the points with a insulating stick like a chopstick or something. I'm sure that will be easier than kicking a 750 twin... possibly the hardest Kz to kick over due to the sheer cylinder size.

But make sure the spark has a path from the coil back to the coil. In other words both plug wires should have a path to each other or to a common piece of metal. The plug wires don't have to go to ground, but it's fine if they do. The total gap in the spark circuit should never be more than about 1/2" or you start stressing the coil too much. People will sometimes leave plug wires unconnected and crank over the motor. That can kill coils quickly if the spark can't dissipate. In that condition, you will see excessive arcing at the points.

Also, don't leave the ignition turned on too long or the coil might heat up too much. Monitor the temp of the coil with your hand if you do the test for an extended period. It should eventually get warm but not so hot you can't touch it.

I definitely feel your pain. . It can be extremely frustrating to be burning up coils left and right. (and expensive!) And if it's stranding you constantly makes the situation even worse.

There HAS to be something that is being overlooked. Mismatched parts / impedances? points improperly installed? bad grounds ?something. This is why I posted some ignition coil theory. If you know how something works, it makes it easier to fix. This is another copy / paste from googling ignition coil resistance ; "What causes ignition coils to keep going bad?
The leading cause of premature failure of an ignition coil is due to a worn or bad spark plug ignition cable. A bad spark plug ignition cable will have a much higher than normal resistance. ... This excessive voltage creates a high amount of heat which consequently melts the coil's wire insulation.Sep 23, 2016"

www.google.com/search?q=ignition+coil+pr...ceid=chrome&ie=UTF-8

As others stated, never let a coil spark without a complete path to the other lead. It can cause internal arcing and ruin the coil.

It sounds like others like the Chinese knockoffs, and I personally have no experience with them, except my knowledge of how cheap the Chinese aftermarket reproduction parts can be.

I am curious why you kick start the bike.? Is there a charging system or starter / battery problem too?

From info in my service manual, the >total< secondary impedance should be ~20K-25K ohms, plug cap to plug cap. This includes the 5K ohm plug caps in circuit. Plug caps themselves are both ~5K ohms each with copper ignition wires -0- ohms in the wires. My bike uses non-resistor plugs.

Make sure all of these parts / resistance readings are correct. More resistance will cause a coil to arc internally. By taking another look at everything hopefully will expose what is causing the problem.

When I have repeated problems, it usually boils down to something I am overlooking. I do hope some of the info we have provided helps you sort this out.

Old-kaw brings up a good point about the wires and caps...
When you changed the coils, did you replace all of this other stuff as well? ...that is plug wires and plug caps and plugs, and more importantly only one of them is of the suppression/resistor type?

Replacing a coil can make a bad plug wire or cap start working for a little while, but during that time the coil will getting very stressed and the points would probably arc more than they should. (Points do arc a little bit normally, but much worse when the coil is under more high-tension stress.)

loudhvx wrote: Old-kaw brings up a good point about the wires and caps...
When you changed the coils, did you replace all of this other stuff as well? ...that is plug wires and plug caps and plugs, and more importantly only one of them is of the suppression/resistor type?

Replacing a coil can make a bad plug wire or cap start working for a little while, but during that time the coil will getting very stressed and the points would probably arc more than they should. (Points do arc a little bit normally, but much worse when the coil is under more high-tension stress.)

My first post on this topic with the pic of my truck coil and coil wire arcing, would be equivalent to a bike coil arcing internally. The secondary resistance is a big factor on any coil living the ripe old age of 2 - 3 hours. lol (plugs, wires, caps, etc.) Those yellow accell "racing wires" and "high performance" neato resistor plugs aren't really an "upgrade".

With folks asking if he's checked it with some super dooper electro-tester that NOBODY has sitting around, while overlooking the real important things like secondary resistance gets overlooked. Sometimes it's the simple things that usually are just assumed to be right.

OK! So sparks flying through points while engine is running means coil is going path of least resistance ie. if resistance is way high on plugs side, the coil will put most of effort into arcing points, still causing bike to run, but not giving the engine its full potential power to the plugs? I have checked resistance before but I will do it again and make sure (note I have done it before so I dont ignore good advice) that all resistance is in correct range.

To make certain, high tension wires should have no resistence? like .001? And plug CAP to plug CAP should read in the 20000 range?


Thanks again for all the helpful insight!

If you mean by super dooper electro tester a dwell meter I actually do have have several 'sitting' around however, mocking one up is hardly rocket science. All you need is a 360 deg proctractor available from any stationary store and a simple bulb circuit tester.
The dwell on a 650 is 180 -195 deg therefore simple to get within that range using simple tools. I haven't set a set of points any other way for at least 30 years. If the timing is correct and the dwell is correct the points gap must be correct.
If your using feeler guages to set the points you have no real idea of the dwell with the resulting arcing.

uh-oh....

Charles 750B wrote: uh-oh....

No issue Charlie, if the whole world had the same thinking your thread would be one answer long. Options to look at is good and will eventually resolve your issue. Thats why forums like this are great, multiple input.