e series for my 250ex

[WickedRider]

ok i have finally decided on the wb e series complete for my 250, i was wondering if any1 thinks i might have to rejet?

[RideRed250ex]

When I first got my pipe i ran it w/ out jetting it and it would cut out and backfire quite a bit but i could still tell the power dif. but once i got it jetted it ran a lot smoother less backfire and still feel more power out of it...so i def. spend the little extra money to get it jetted its better for your engine to get it jetted on top of that, and u have the K&N filter so you will need to get it jetted im sure it would be worse running with out jetting for the K&N ... :)

[Bad Habit]

Are you gonna run with the airbox lid on or off? Deffinitely jet up if no lid. With a yoshi slip on, I had to go up to a 110 main with no lid.
The affects of jetting on these things almost seem exaggerated. It pops and backfires like crazy when it's the slightest bit lean. It falls on it's face bad when it's rich.