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.

 

Sounds like a jetting problem.

 

If it sounds like its at the top end....just buy a step higher in a main jet....then put in the next size bigger jet and see if that doesn't help out with your throttle cutting out on top end...you should be getting good airflow with no air box lid.

 

i thought it sounded like something wrong witht he jetting too, but it wasn't doing this before i geared down, do you have to rejet if you regear, or is it a possibility that it just started acting weird at the same time that i geared down by some freak occurance?