i have a 1993 580 that has a very high idle when cold and i think it is sucking air into the crank case....so where is the most likely spost for it to do so??

maybe intake gaskets or maybe even crank seals, just check them out with starting fluid. Good Luck!

Make sure you keep the airbox on so you don't draw any starter fluid into the engine or you'll get a false "positive" when checking for vac leaks.

crank seal or carb. flanges most likely.

Not unusual to idle high wne cold, then proerly when warm. Does it perform well when riding it?

My 94 580 XLT does the same. Runs up to 4000rpm when I first start it. I have to play with the choke to bring it back down. Once it's warm and it works perfect and idles at 2000 +or-.

it runs good when warm but if ridden for long hard time it barelly idles...ill try to ceck the seals...

When it's fully warm, what is the idle at? Should be around 1900rpm according to the manual.

its at 1950 when warm