Hi bullet, the front tyre is brand new (only has 5 or so miles on) and the back tyre pressure is spot on for the road conditions around here (not the best on a good day) The belt is doing as it should do, with fluid movement when throttle is opened, there are no jams etc... The belt itself is brand-new, again, only covered approx. 5miles. Im off to pick up some new lights tommorow, as my headlights blew the other day, so shall stop by tesco's to double check tyre pressure. The other thing that was suggested is it could be something to do with the time management of the engine (No idea on what that is), the Carb (recently been stripped and cleaned), or the one way electronic fuel control -- A little black box next to the carb .. However the bike itself is running clean as a whistle, she is not smoking or coughing, so that for me rules out trouble with the engine. (That and she is not drinking oil). Nath