It's a little difficult to comment on the Kwacker problem I'm afraid, the same applies with most hi-tec bikes of today with everything being electronic etc. In a nut shell it could be anything really. No doubt things like spark plugs and air filter have been replaced already
daft as it seems, double check your garage has actually looked at the carbs and made sure they are not loose. have had this problem on a couple of vehicles.
sure sign is drinking fuel, and it will cut out more when its warm.
hope this helps a bit
