Carb problems...

This has got me pulling my hair out....

2 sleds, setup identical. Both have the 97 Liberty 700's in them and have been converted to the Mikuni rack carbs. One has developed an issue, it is loading up real bad at idle and it just sits there and burps/spits/sputters and sometimes wont clean up enough to take off. Tore the carbs completely apart and could not find anything wrong, cleaned everything real good and had the same result. Inspected the reeds to find one tip of one of the petals was missing, actually looked like it was burned off as the rubber cage was melted right in that spot??? Replaced the reeds with VForce 3's, same result.
Took the carbs off the other sled and put on this one, runs fine... so I am assuming it's something in the carbs, they are both setup exactly the same and both have ATACC's installed although I am ruling out the ATACC since I left those the same when I switched the carbs.

Is there something internal on these carbs that could be wore out or that I'm overlooking? Ran great earlier in the season.

I'm not so sure it is. I'll pull a plug wire off the one I know it's affecting and see how it runs. Once it gets up to 3-3500r's it cleans up and runs good.

One of the o-rings that goes on the air screw is pretty beat up, would that affect much??

The screws all look good.

Took the covers off the front and did not see anything that looked bad with the slides, also didn't see any glides.

I put my carbs on the other sled and the problem followed the carbs, so something is off kilter with them.....

Don't plan on it before we leave Thursday. Looking at buying another set of carbs and getting them expedited.

You got some magic to work on them????