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Electrical Issues with 1976 KZ400D

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14 Apr 2020 12:37 #823353 by HeiShadow10
Electrical Issues with 1976 KZ400D was created by HeiShadow10
I recently purchased a 1976 KZ400D motorcycle. The previous owner stated all issues with it before purchase, no coil, old spark plugs, no battery; of course; but motor is free an plenty of compression. Right now, I have a no spark no start situation. Things I have done: 1) new 13 AH battery, 2) new spark plugs, 3) new coil, 4) new points; set and working, plenty of spark off points, and 5) new condensor, which I'm still waiting to come in. Now my question is, still a no spark situation. I measured the new coil and it read bad, so I purchased a new coil and it measures within the working limits. Still no spark, checked battery, why not, good battery; I am getting 12.95-13 volts to battery side of coil. Reset points, why not. I am going to get new spark plugs because I think the ones I purchased are resisted , now correct me if I'm wrong, but cannot have 2 resisted parts in coil? So, my question is, what am I missing because I am getting frustrated with it and I personally like the bike, I don't much care for the new designs of bikes, but that's just me. So, please let me know what you guys are thinking. But, I've checked and replaced the battery, coil, points, waiting on condensor, and going to get new spark plugs.

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15 Apr 2020 10:19 #823424 by loudhvx
Replied by loudhvx on topic Electrical Issues with 1976 KZ400D
Do you have a manual? It might have some troubleshooting hints.

Did you measure the voltage on the negative side of the coil while slowly turning the crank? It should pulse between 12v and near 0v. If it does that, then you need to check the condenser if it still doesn't spark.

How are you checking for spark? You have to make sure both plugs have a complete path to each other. If one can't spark, the other won't spark.
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15 Apr 2020 11:34 #823431 by Kidkawie
Replied by Kidkawie on topic Electrical Issues with 1976 KZ400D
First thing you need to do is unplug, clean and lube every bulk connector in the harness. You cant test components with a bad harness.

1975 Z1 900
1994 KX250 Supermoto
2004 KX125
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15 Apr 2020 12:12 #823433 by loudhvx
Replied by loudhvx on topic Electrical Issues with 1976 KZ400D
Like Kidkawie says, cleaning the contacts would be a good idea, but I wouldn't lube them with dielectric grease. That is an insulator and eventually wicks into the connections and prevents contact. A conductive grease would probably also be a bad idea. I would just use Deoxit on the contacts and clean them only.

I've spent hours cleaning and/or replacing connectors on bikes that had dielectric grease applied creating a bunch of intermittent connections over time.
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15 Apr 2020 17:17 #823451 by HeiShadow10
Replied by HeiShadow10 on topic Electrical Issues with 1976 KZ400D
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.

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15 Apr 2020 17:29 #823452 by HeiShadow10
Replied by HeiShadow10 on topic Electrical Issues with 1976 KZ400D
Tomorrows project is to clean all electrical connections, but please let me know the proper voltages and procedures to checking the coil, I feel like I am missing something. I put the new condensor in today because it finally came in, tried to start and still no start. Points are still throwing spark, but finally saw not a constant spark, probably moisture or dirt on contact point. Probably a stupid question, but could the voltage regulator be causing issues, measured the power at the coil and am loosing a volt from battery. Now please correct me, but the coil power comes from starter coil to the handle bar control and then to the coil, or does it go straight to coil? I just feel like I am missing something simple and I am just chasing my tail. All the parts that I have installed are new and working, as far as my dumbass knows, but the coil, points, condesor, and spark plugs.

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16 Apr 2020 04:59 - 16 Apr 2020 05:02 #823471 by loudhvx
Replied by loudhvx on topic Electrical Issues with 1976 KZ400D
It's normal for the points to spark, and not necessarily be consistent.

How are you checking for spark at the plugs? Do you have both plugs out and laying on the head?

When everything is turned on and ready to run, most of it will have close to battery voltage on it (nominally 12v), but there could be small drops across the fuse and switches.

The wire between the coil and points will either be near 0v if they are closed, or 12v if they are open.
A good place to check is where the coil wire (i think it's blue) attaches to the points.

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Last edit: 16 Apr 2020 05:02 by loudhvx.
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19 Apr 2020 14:07 #823688 by HeiShadow10
Replied by HeiShadow10 on topic Electrical Issues with 1976 KZ400D
After a fruitless weekend, no changes, but did find some things out. Coil is receiving 11.39 volts from battery, coil is receiving 12.10 volts from points, ohms between yellow wire from battery and blue wire from points is .42 and ohms between plug caps is 22.9. Battery is fully charged, still cant seem to get a spark, with either plug grounded to engine block, spark plug tool, or attachment for meter. But, did find out something though, off topic, bad vacuum cup for right carb. Going to try different plugs, and possibly different caps. Still haven't found where my loss of entire volt, but did find .75 of a volt is being lost in starter coil.

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19 Apr 2020 17:34 #823694 by loudhvx
Replied by loudhvx on topic Electrical Issues with 1976 KZ400D
You really need to focus on the blue wire and the difference when the points are open versus when they are closed.

If the voltage on the blue wire is the same when the points are open versus closed, then something is wired wrong or the points aren't fully moving as necessary.
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20 Apr 2020 20:49 #823787 by F64
Replied by F64 on topic Electrical Issues with 1976 KZ400D
This reminds me of a screwup I did last year.
The wire going from the points to the coil was always grounded...The washers that isolate the points' terminal hold down screw were in the wrong order....the points' terminal needs to be isolated from ground when the points are open and grounded when the points are closed.
Loudhvx is saying the same thing.
You can use a test light as well. Put the clip on 12V+. Check the tip against a good ground. Then put the tip of the light on the coil terminal coming from the points. Turn the engine over. LIght should turn off everytime the points open.

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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23 Apr 2020 13:48 #824091 by HeiShadow10
Replied by HeiShadow10 on topic Electrical Issues with 1976 KZ400D
Sorry guys been pretty busy with other things, but will focus on the points this weekend. Thank you for the advise and I will let you guys know here pretty soon what I found out.

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03 May 2020 12:16 #824876 by HeiShadow10
Replied by HeiShadow10 on topic Electrical Issues with 1976 KZ400D
Okay finally able to dedicate one weekend to the motorcycle. Worked on the points, getting 10.95 from points and 0 when moving shaft by hand. So points are opening and closing properly. Went back through electrical system and found 0 breaks in wire, all plugs are connected and cleaned, battery was a little low on charge put on battery charger and tried again, no luck, the only thing is the starter coil, getting 12.95 into and 10.95 out of coil, could that be an issue. Just about to lose it due to these damn problems, purchased a new spark check tool, goes into resistor and plugs onto spark plug, still not showing spark, with new or old tool, everything checks okay except for starter coil and no spark. Going to get new plugs, just for shits and giggles, put compression tester on engine, good compression, took exhaust pipes off and other exterior motor covers and checked for obstructions, none. Going to get some parts and see if that helps or not. I don't like to just throw money at things, but I'm just about to.

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