1984 GS1100GK Spark Issue?

[redhawk]

I picked up a 84' GS1100GK a few months ago, I'm not getting a spark to #1 Cylinder. I have adjusted the valves(good compression on all cylinders) and have gone thru the carbs. It runs. When I pull the #1 plug and ground it to the head, it will not spark, when I pull it away from the head it will then begin to spark. The coil tested fine. Am I looking at a CDI issue? or a ground issue? Any help would be appreciated.

[Nessism]

Sounds like a bad plug. You might want to try another plug in the same cap. The same coil fires #1 & #4, so if 4 is firing the coil and ignitor are fine (GS bikes do not use a CDI).

One part of basic maintenance with these old bikes is checking the plug cap for resistance and making sure the attachment to the high tension wire is solid. You can unscrew the cap from the wire and snip off a small piece of the end to make sure you have a fresh attachment (low resistance). You can also pull the wire out of the coil and replace it but it can be fiddly work to get the remnants out of the coil wire tunnel.

Good luck

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[redhawk]

I did as you suggested(re-did plug end, tried new plugs) and still no spark to #1 cylinder, again, once i take the plug away from the head it will start to spark. I assume that when I thread the plug into the cylinder it grounds out. The plug is wet when I inspected it. Any suggestions or thoughts?

[redhawk]

Does anyone have any idea's why my spark disappears when I ground the #1 cylinder sparkplug to the head, I have spark when I pull it away. My #4 cylinder is firing. Any help would be much appreciated. Thanks.

[koolaid_kid]

Sounds to me like the plug cap is shorted out. Try swapping them around. Did you snip the coil wire like Nessism said? That is very important.
The plug is wet because it is not firing.

[tom203]

Yeah, swap 1 and 4 plug wires (dry off spark plug). Have you pulled off tank to inspect wire connections at coils?

[redhawk]

Still stumped? I've followed everyone's advice and did the suggested items. I have switched the coils and am still not getting any spark to #1 cylinder. Any suggestions? do you think I have a ignitor issue? Any help would be appreciated.

[Flyboy]

why my spark disappears when I ground the #1 cylinder sparkplug to the head, I have spark when I pull it away

Let me understand this, if you lay the threaded part of the plug on the head, there is no spark between the electrodes.
But if you hold the spark plug away from the head slightly, there is a spark between the body of the plug and the head? Is that correct?
If so, you have a bum plug, replace, it is shorting internally, probably from being dropped which has cracked the ceramic insulator.

[redhawk]

it's definately not the spark plug, I've rotated several new and used plugs and still get the same results. My only way to determine if the cylinders are firing are touching the exhaust pipes, #1 is clearly cold, #2 heats up quick, #3 heats up slower, #4 heats up quick. I have gone thru the carbs, I have adjusted the valves, I have rotated the plug wires, coils, tried new plugs..... ????????

[Nessism]

#1 & 4 fire off the same coil. Try switching plug wire #1 with #4 and see what happens. If #1 still doesn't fire the problem is not the ignition.