I installed a dynoport pipe and in order to make it run well at low rpm, I had to lower the needle two notches so I'm in the first notche ? Is it normal or common ? I run at the sea level, my main jet is a 260. I also tried a much smaller pilot jet and it did not help... Am I the only one among all the guys who have modifed 400 to make the mix poorer with a tuned pipe ???

 

Looks like your main jet is way to big. If you are lowering the clip it seems that you are running very rich. Put in a smaller jet and then you can raise the clip again. Dynoport is not the best of pipes to put on a Polaris.

 

260 i think would be way to big 2 im running a 160 with mine and i have a whitebros and K&N it works great