paul one thing that may have happened is the main jet may have fallen out or comevery loose in the carb,has the bike ever been upjetted for a race exhasut ever do you know as if the main jet is too big it will also do this.tryn it for a minute with the air filter foam out and see if it goes better ,if it does then its too rich but done leave the filter out for ever sort the cause out and replace the filter.
adam bike doctor(of milton keynes motorcycle centre), January 2011
