Hi all I have a naughty DR600. It will be running fine then suddenly, like someone has flicked a switch, the revs will rise instantly to anywhere from 1/4 to 1/2 open. Thefter a while, it will just as suddenly drop to normal again. I stripped the carb down and everything is fine. Replaced the O ring between the carb mounting flange and head. Checked the cables and everything seems fine. Any ideas greatly welcomed.