Well my '03 SP 600 would always sputter when you gave it gas or when you are riding and you let off the throttle and then hit the throttle again....Well I fixed it by just lowering the E-Clip one notch on the jet needle and that fixed the problem and it has alot more power on the low end...lean from the factory, but that was the case. Typicaly they come rich....well this could fix any low end sputter by richening up the eclip.

 

Did you move the clip to a lower groove...which effectively raises the needle and makes it more rich, or did you do the opposite?

 

yes, one notch down but you might need two pending on how lean it is....