okay so my 1997 katana 600 starts up fine with the rpm at or around 1000 but after about 15 minuets it goes all the way up too 4000 i tried adjusting the idle adjustment screw but when i turn clockwise the idle goes up but when i turn counterclock wise the idle drops but stays at 4000 no matter how much i turn. So what can be the problem. if anybody sudjest cleaning the carbs do you think emptying the tank and putting one of those autozone carburetor/fuel cleaners in the tank will work? if not what can it be?