sound familuar to you to? well thats because people seem to just make a topic about this again and again and again and again, when you fit a pipe and your bike "bogs down" it is a common problem, stock exhausts are made to make power low down and not rev, the opposit of a sports pipe. the rollers set the opperating rpm of your engine, you need to drop the roller weight, upjet slightly and fit some stiffer clutch springs. read this http://www.scootershack.co.uk/viewtopic.php?f=25&t=12834 and this http://www.scootershack.co.uk/viewtopic.php?f=25&t=12835 if you have any more problems post in here, dont make yet another topic about an aerox that bogs down, theres 10 topics below this one this week!!