I have a 96 Formula STX LT (583) with 5400 miles. It starts fine and idles properly (@1400rpm). Once warm and riding, when you come to a stop the engine revs @ 3000rpm (clutch engages at 4000rpm) for @ 2 minutes then eventually drops back to 1400rpm. Just bought it. In mint shape, never abused. Spring I plan to clean carbs and RAVE (among other things). Any thoughts/ideas? My brain is full for the week and can't think anymore. Thanks for the input.

The idle screws are not turned out the same amount. One cylinder is trying to pull the other one faster, but eventually gets dragged down.