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Electrical Issues with 1976 KZ400D

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03 May 2020 14:01 - 03 May 2020 14:03 #824895 by loudhvx
Replied by loudhvx on topic Electrical Issues with 1976 KZ400D
You've used the term "starter coil" a few times now, but that is not a common name for anything related to the ignition.
There is an ignition coil which connects to the spark plug. And that is the only coil on a points system related to ignition.

There is a thing called a stator which is made up of coils, but that is for the charging system and won't affect ignition if you have decent voltage from the battery, and you report near 11v which should be enough to create spark.

There is a field coil, but that is also related to the charging system.

There is a starter-solenoid which has a coil in it, but that is a relay for the electric starter. Then, of course, the electric starter motor has "coils" in it as well. But neither of these would be related to the ignition.

Since you have 11 volts on the points, and the points go to 0v when you rotate by hand, that leaves a few likely possibilities: Either the ignition coil is bad or the condenser is bad, or possibly one or both resistor caps is bad or one or both plugs is bad.

Are you getting a lot of spark at the points themselves? That usually indicates the condenser might be bad.

Again, how are you actually checking for spark?
Do you have both plugs connected to the coil?
Do you have both plugs out and sitting on the engine?
Are you checking in a dark area so you can see the spark?
Last edit: 03 May 2020 14:03 by loudhvx.
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03 May 2020 14:32 #824902 by F64
Replied by F64 on topic Electrical Issues with 1976 KZ400D

HeiShadow10 wrote: I do have a manual and have tried almost everything they suggested except cleaning connectors and that is tomorrows project. Please refresh my memory on the measurements on the coil and the instructions. I feel like I'm missing something. As of right now, I have an electric multimeter and am not picking up any voltage from the points on the connector on the coil. I just replaced the points and finally the condensor and I have continuity from the points to the connector by coil, so the wire is good, not broken or damaged, doesn't show a ground, so to me the wire is fine. The points are showing sparks when I remove the cover for it and turn the motor over, but not a constant spark, so probably dirt or some light moisture on points, will clean tomorrow. Probably a stupid question, but would the voltage regulator be causing a fit or issues. I double checked the voltage on the coil and I am loosing a volt from battery to coil, I'm thinking most likely a bad connection. Now, please correct me, the coil power comes from the battery to the handlebar switch to the coil or does it go straight to the coil? I just feel like I am missing something big time and I am having a major brain fart.


The points wire must show a ground when the points are closed.

81-KZ440-D2.
Louis Dudzik's GM HEI ignitor conversion installed 2015 s3.amazonaws.com/gpzweb/Ignition/GPZgmHEImod.html
Motogadget m-unit blue installed 2017.
LIC, NY
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03 May 2020 14:51 #824906 by HeiShadow10
Replied by HeiShadow10 on topic Electrical Issues with 1976 KZ400D
There is an ignition coil that is directly connected to the positive of the battery, the yellow/orange wire comes from, a black wire that comes from the coil and of course a negative that connects to the battery. I am going to replace the resistor caps and the spark plugs. I have an actual spark checker, you connect one end to the resistor caps and the other end to the spark plugs, and it will flash when the ignition system is working properly, of course it will not work when it does not work, all it is is a window to see spark, I also have a clamp for my digital meter that will measure actual voltage in the coil wire, nothing is showing any type of voltage going through the coil wires. I have a spare coil I am going to swap out and try that. I will double check the points again.

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03 May 2020 20:44 #824918 by F64
Replied by F64 on topic Electrical Issues with 1976 KZ400D
Connect the spark checker as follows.
-one end to spark plug wire
-other end to ground
crank to see if you have spark

81-KZ440-D2.
Louis Dudzik's GM HEI ignitor conversion installed 2015 s3.amazonaws.com/gpzweb/Ignition/GPZgmHEImod.html
Motogadget m-unit blue installed 2017.
LIC, NY

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04 May 2020 03:08 #824923 by Kidkawie
Replied by Kidkawie on topic Electrical Issues with 1976 KZ400D
You said you installed a new coil, points, plugs and condenser in the first post. Now you are buying another coil and another set of plugs? The service manual explains how to test the coil, if you did that or actually bought a "new" one you can eliminate that.

1975 Z1 900
1994 KX250 Supermoto
2004 KX125
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10 May 2020 13:13 #825395 by HeiShadow10
Replied by HeiShadow10 on topic Electrical Issues with 1976 KZ400D
I am very excited to report that she finally is up and running. I decided to invest in some new carbs, as I was thinking the old ones were not operating properly even after taking to a motorcycle shop to do an inspection after I disassembled and cleaned. Decided to invest in the VM 30 mikuni carb kits, came with everything needed. Came in, tested all electrical again and found one pinch in points wire after all the times I looked at it. Replaced wire, installed new carb kit, installed new petcock valve, filled tank with gas, and low and behold she fired right off, no stutters or nothing. She is running strong with no motor ceasing, chirping, no nothing. The only thing is, is what do your KZ400s idle at. Its about 43 outside when I started it, it ran for roughly 10 minutes at 1500 rpm, after that she started to rise to 2000 and started to settle down around 3000. It doesn't sound like its idling that fast, but thats what the gauge says. If you could shed some light on if thats a little normal or what it should be idling at. But, I would ;like to thank everyone that helped.

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10 May 2020 17:31 #825415 by TexasKZ
Replied by TexasKZ on topic Electrical Issues with 1976 KZ400D
The factory service manual has that information. You can download one from the Articles section of this website. I suspect the idle should be around 1100.

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