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Discussion Starter · #1 ·
I am in search of a vintage Kawasaki Electro Tester (57001-980), or a manual, or a schematic so that we can understand what the third prong(electrode?) is for. First of all, here is a picture of the tester:

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On the tester is a little window on the right hand side that lets you see the spark that is generated by the ignition coil you are testing.
There are two electrodes that can be moved apart to see how big a gap the spark can jump. What puzzles us is the third prong (electrode?) that is very close to one of the two spark jumping electrodes. See picture below of the electrode arrangement. Does anyone know the function of the third electrode? Yamaha and Suzuki also made use of very similar test equipment, so a schematic for those would help us also.

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I believe it is referred to as a teaser electrode. Its purpose is to address the problem of time lag when using pointed electrodes. Suzuki's version of this tool was supposed to test CDI boxes as well but I never found it to reliably diagnose. As I remember if it said the box was bad it was bad but if it tested good it might be good or bad.
 

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Discussion Starter · #3 ·
Thanks. Do you have any idea what the teaser is connected to?
From what I can tell, the Suzuki, Yamaha and Kawasaki electro testers were all built by the same company.
Would love to find a schematic.
 

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Of course it was a long time ago but I do agree, the tester pictured, other than lettering looks identical to the Suzuki unit.

I do not know what the third electrode was connected to. I offer the following pure speculation. My speculation has a major flaw, perhaps you can offer alternate explanations or refine my speculation.

We are working in milliseconds. I can understand that for a very brief time the pressure behind the emitting electrode, though increasing is not sufficient to bridge a large gap, so we present a very narrow gap that encourages the low pressure electrons to start flowing. Even though the pressure is low the electrons are teased into an initial flow. Because we are talking milliseconds, long before there is a visible discharge to the close/teaser electrode pressure/voltage quickly rises to the point that it will jump the greater gap. This would allow a more consistent, time wise, representation of what spark is occurring. The major flaw here why does the high pressure spark not simply jump to and discharge thru the close electrode. WFO, I know you have an extensive mechanical background, please feel free to add, challenge my theory. Look forward to someone clarifying and explaining this concept.
 

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Discussion Starter · #5 ·
An interesting theory 1981GPZ550. I think what we really need here is an electrical engineer. Preferably one who has designed ignition systems. I recently did a deep dive into how an ignition coil and spark plug function. What I thought was a relatively simple process is in fact extremely complex. The topic was being discussed by electrical engineers or people with a heavy background in electronics. It was heavy into physics, math and electronics.

Most of their talk went way over my head, but I came away with a much better idea of just how complex the topic really is.
Sadly, there was no talk about electro testers, but I did learn that resistor caps and resistor wires will have almost zero impact on the strength of the spark (contrary to popular belief, including mine). On some scenarios they calculated a voltage drop of only 400 volts. No big deal when the coil is capable of 20-30,000 volts. One key point they made is that resistance does not actually occur until the spark has happened. There has to be a flow of electrons before a resistance occurs. The resistance comes from things like cylinder pressure, gap distance, condition of plug etc.

Getting back to the mystery third electrode. My theory is that it provides a safety path for the spark after the gap is too large to be jumped. The flaw of course is the same as yours. Why does it not jump there in the first place?
My thought was that if you open the gap too wide, it may damage the coil if the energy has no place to go, thus jumping the short gap instead.

What I would really like is to get my hands on an old electro tester and tear it apart to see what makes it tick.
My shop never had one, but we had a much cheaper knock off that only used two electrodes.
 

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I agree, a lifetime of hands on experience does not necessarily provide a compressive understanding of ignition design or physics. I love to study theory, and hope there is, or will be someone out there who can explain this in detail.
 

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I continually marvel at how many things we took for granted in the seventies and early eighties. All of those Windjammers, Kirker's, Lester wheels, never thought that era would end. Thought the electro tester was the last word in diagnostics. Sure do miss the UJM days.
 

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Discussion Starter · #8 ·
I miss the old days too.

Here is our crude coil tester in action. It was originally made by Snap-On and we are currently modifying and upgrading it.

In this video we are testing an ancient automotive coil and jumping a gap of about 15mm. Oscilloscope measured about 15,000 volts. The cell phone used to capture the video did not like the spark or the EMF from the spark which is why the spark appears to disappear and reappear. In fact the spark was continuous.

 
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