the problem is the expansion chanber exhaust you have on it,they are good but need alot of back pressure to get the engine running right,i would try some lighter rollers like 5 grams or try taking 3 rollers out and leave 3 in in a triangular posistion.as the rollers do not let the engine rev fully it doesnt allow enough exhaust gases to go through and create the back pressure
adam bike doctor (of milton keynes motorcycle centre)
January 2011