Intermittent firing # 2

[OldVet66]

My number two cylinder is firing intermittently. At an idle it barely fires at all, the pipe is 186 degrees when the others are 268 degrees. Pull the spark plug wire and there is no difference in the idle, it just lopes a little, it seems to do that anyway. It will jump spark as the plug wire is pulled away from the plug. The bike seems to run great otherwise. This is the second new plug I have had in this location, and neither plug is coloring. It still looks like I just put it in, when the other three color immediately. Can one side of a coil go bad?

[chef1366]

Unscrew the spark plug cap, cut the wire a bit and put the cap back on.

[OldVet66]

Already did that, it made it run a lot better, but didn't fix it. I have another set of coils on my '79 that I could try. Do you think running it previously with the bad connection might have damaged the coil?

[OldVet66]

I believe I had a bad plug cap. I switched it with one off of the '79 and there was a whole lot of difference. I couldn't test it properly because it was dark and deer dodging time up here next to the mountain. It was into red line faster than I thought it could, so I'll test it thoroughly tomorrow when I don't have to worry about dodging critters. Thanks for pointing me into the right direction .

[Steve]

Another test, for those that read this, is to simply swap the plug wires for 2 & 3.

If the problem follows the wire, you have a good clue.

.

[almarconi]

When was the last time you cleaned your carbs?

[OldVet66]

It's a rebuild of "George's" rebuild (a long story), new petcock and tank. When I changed the cap, it jumped alive. If the plug starts to color normally, problem solved. The caps were replaced along with the coils, apparently one of the new caps broke down.

[OldVet66]

I replaced the coils with the ones off the '79 and all the pipes are running the same temperature now. I see a set of Dyna green coils in my future. One more problem put to rest.