81 kz750h no spark on 1-4
- coreybee78
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81 kz750h no spark on 1-4
14 May 2017 06:40
So I changed my plugs about a week ago. A few days later I started the bike to leave work and noticed that it didn't sound right. I discovered that cylinders 1-4 were not firing. I got this bike on a trade and it had been very poorly maintained so I replaced the coils, plugs, wires and caps. Still nothing so I tracked down an ic igniter and replaced that too. The ignition system is still the factory electronic system. I checked ohms and got around 450 on both sets of leads which I believe is good. Now I'm pretty much at a loss. I'm pretty good with mechanical and electrical work, but I've done everything short of tearing apart the wiring harness and replacing the ignition. This is my daily transportation so any help would be great. I did notice that when I revved the bike after a little while they would fire a few times and cut out again. At one point they continued firing until I turned off the bike. Nothing since then.
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- loudhvx
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Re: 81 kz750h no spark on 1-4
14 May 2017 09:03
Did you check for spark by pulling the wire off the plug? If you do that, you must make sure the other plug wires also have a path to the engine otherwise you can damage the coils and igniter.
I posted a drawing of how to bench test the ignition if you have a decent battery around.
www.kzrider.com/forum/4-electrical/60581...?limitstart=0#761163
I posted a drawing of how to bench test the ignition if you have a decent battery around.
www.kzrider.com/forum/4-electrical/60581...?limitstart=0#761163
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Kz550 valve train warning.
Other links.
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- coreybee78
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Re: 81 kz750h no spark on 1-4
14 May 2017 11:45
The only way I could get a spark was swapping the black and green wires. I read through your thread and several others before I got to this point.
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- loudhvx
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Re: 81 kz750h no spark on 1-4
15 May 2017 08:14 - 15 May 2017 08:14coreybee78 wrote: The only way I could get a spark was swapping the black and green wires. I read through your thread and several others before I got to this point.
You're saying you had spark on the 2-3 coil, and when you swapped green and black wires to the coils, you then had spark on 1-4 (but not on 2-3), correct?
If that's the case, then the next step is to swap pickup wires.
Put the green and black wires back to where they started to avoid confusion.
On the pickup wires, swap black with yellow, and blue with red.
I forget if it's easier to swap them at the igniter harness or the pickup harness.
If the problem stays on the 1-4 coil, the igniter's 1-4 circuit is bad.
If the problem moves to the 2-3 coil, the blue-black pickup is bad.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Kz550 valve train warning.
Other links.
Last edit: 15 May 2017 08:14 by loudhvx.
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