ok, let me start off by telling you what i have on my 03 z400. I have the alba jet kit, alba slip on pipe, k&n filter with outerwear and no airbox lid. I recently geared down to 13:41 to get better acceleration. Well, my problem is that whenever i open up the throttle all the way it starts to cut out. IT sounds like its hitting the rev limmiter, but im not sure. I think it might not be getting enough air, or not enough fuel, i dont know how to tell, also, it might have some back pressure. These are just some of my thoughts. I really need some help to get my z running better. Any help is wanted. If you need to know more to help then just ask. Any help at all is wanted.