Jetting for ESeries Exhaust

[Carz]

I'm currently running my 400EX completely stock. Im going to put a K&N Air Filter, and a White Bros. E-Series Slip On, on my quad. Im just wondering how much I will have to change my jets in order to make it run well. Just thought I would ask before I start pissing around with it.
Thanks
Adam

[RytM1]

When I had those mods, I bumped my main up to a 155.

[knaegeli]

I live at sea level and am running stock engine e-series slip on, k&n filter with modified airbox. I run a 160 main and drop the clip one position on the needle. It runs great! hope this helps!

[400ex28]

I have an w bros R4 and K&N filter and ive been running 155 man jet...