fire only when wire is loose

[jimpapa]

followed ed's tune-up guide and everything was humming along nice.
or so i thought
would run the bike for a few minutes and vary the throttle, let cool down and check for leaks
an hour later would do again and re check timing.

about 4th time wasnt getting any light from strobe on left side
when i was checking the plug wire i pulled it off and just as it came off the light started working again and the engine revved up.
put wire on tight and nothing.
only works when theres a gap betwen the plug cap and top of plug.
about a half inch away and it fires great
i'm perplexed.
what does this mean?

[mike in idaho]

The spark plug is fouled, put in a new one.

[Seralan]

Hey Jimpapa,

I have the exact same problem. Did swapping the plug fix it?

Thanks!

[G3]

Mike in Idaho was no doubt right on this one. Every time I foul a plug, lifting the cap off and holding it a bit off the terminal causes the plug to fire. Replacing the plugs with new is the best if not the only option, and they're cheap.