[Vegas Street Rider]

Although kilo 0195 is probably right about the carb needing attention, you could also have an issue with the petcock. Before I rebuilt mine, my idle was all over the place. I had to put it in gear and hold the brake to get it to idle down and then sometimes it would creep back up to high rpms. Having sat that long, it is probably a combination of all of the above. Lacquer has coated the jets and other surfaces and possibly even the petcock and is causing your problems. Seafoam will certainly help alleviate some of the problem but depending on the severity of it, you may have to go in and manually clean it and/or replace jets etc. to get it back to normal. Not expensive if you do it yourself and it would be a good learning process. Lots of info on this site.