i would say in my opinion that the exhasut pipe is blocked up on it with burnt 2 stroke oil,when you rev the bike on the stand does it feel like the air is blowing out of the exhaust freely or does it seem a bit strangled?i would suggest cutting the whole exhasut in half and getting someone to mig weld it back together again after you have removed any bloacked baffled parts.also you can try and get a sharp metal spike thats at least a foot long and hammer that up the tail pipe into the baffles to bypass any blockages this can be an easier option than the welding.very common problem though all in all.
adam bike doctor(of milton keynes motorcycle centre), June 2011
