81 GS550 No spark when in contact with block

[raustin584]

No spark when plugs touch block but pull it away and these a spark jumping from the block to the plug and a small spark in the plug. touching the block no spark in the plug.. Help whats wrong with it? It was running then stop and won't start. Help please!!

[Redman]

I have heard that symptom mentioned before, but dont recall what the conclusion is/was.

Just bumping this back up to the top.

What happens on other plug of same coil?
Does This happen on all plugs?

[raustin584]

spark problem

Yes it happens to all plugs checked all grounds yesterday didn't find anything. Spark still happening between plug outer case and engine block. spark going backwards up inside the plug. Plugs are new like within ten miles. Is there any test I can perform to track it down? I'm new to bikes so please help.

[dietcokeking]

Okay. The spark travels down the plug wire and through the center electrode. If the spark is jumping from the base (threaded part) of the plug to the block it must be travelling through that insulated center electrode before finding its way to the threaded part. The spark must jump off the center electrode to the threaded part somewhere before jumping to the block. If the plug is undamaged, and there are no conductive contaminants inside or outside of the plug, it should be jumping the gap.

Make sure the gap is set correctly. Ground the threaded part (not the L-shaped electrode) to the engine while you make your observations. Make sure you are in a darkened room or do it at night. You should see the spark across the electrodes! If not, I can't imagine what would cause the problem.