I have a 2000 wr400 the bike had been running flawlessly until it was parked for 2 months now when I let off the throttle it runs fast for a while then returns to idle. I have checked the main and pilot jets clean as a whistle, checked for binding at the grips checked the cables and they are fine. Also if I blip the throttle it will instantly return to idle. The valve clearances have been checked recently and are within spec. Air filter is clean blah blah blah is there something I am missing besides pulling the carb and soaking it in cleaner and blowing it out.