Solve this mystery:

[chrishophoto]

I have a 91 Kat 1100.

I have done a lot of upgrades including rejetting and V&H exhaust. I have balanced the carbs, and tuned the air mixture screws etc.

Here is the problem I am encountering. It idles pretty smooth most of the time, but one day, after riding it really hard, I stopped for gas, and when I started it back up it idled pretty rough. Seemed like it was missing on a cylinder or two.

Any thoughts?

[clockwork cdger]

Did you let the fuel get really low? Could have dragged some crap out the bottom of the tank, blocked up the jets.

Dave E

[chrishophoto]

Did you let the fuel get really low? Could have dragged some crap out the bottom of the tank, blocked up the jets.

Dave E

Nope. Tank had a gallon left. and my tank is very clean.

[clockwork cdger]

Check nothing has come loose from the vibrations in the way of ignition parts. have you anything to be able to check the coils, see if they have broken down?

Dave E

[steves]

It happened one day once, or it has been continuing to happen?

[ErrEs]

That's not a lot of info to narrow it down. Did you do a basic check? (spark plugs, carburators, re-check settings on air/fuel mix screws,..)
Does it only happen when idle?

[Wild-Bill]

Sounds like heat-soaked coils. How is it doing after cooling off?

[subforry]

I agree with coil/ht issues. After I get off the freeway and wait a long time at a light my kat will hiccup as I pull way. Feels very much like a fuel problem, but consistently happens. If the light is short, no problems.

I did the coil mod, but have not run the bike since. I am painting it.

[chrishophoto]

Sounds like heat-soaked coils. How is it doing after cooling off?

I didn't think about it possibly being the coils, but that makes a lot of sense. The bike definitely seems to not like the really hot days we have been having, and I can see the coils getting much more heat when the bike stops while I'm getting gas. The bike seams to do fine after it cools down.

I was thinking that maybe a fuel line was getting squashed with the extra weight in the tank, but it didn't seem that the tank had enough vertical play, to make this happen.

Thanks!

[Wild-Bill]

The tank is pretty solidly mounted so I doubt that it's moving at all. You can check the fuel lines with a flashlight. It won't matter if the bike is warm or not, though.

There's got to be a good coil out there that would provide the same or better spark than the stock ones and fit in there without costing an arm and a leg. It's not like there's anything real cosmic about matching coils. Wonder if this one would work: https://www.denniskirk.com/wsm/ignit...prd/200095.sku