I want a little more power ..... seems like the first thing to do would be to ditch the factory air filter and get a K and M. But do I need to do anything other than install the new filter? Do I have to re-jet as well or is it as simple just installing the K and M?

 

first of all it's k&n and i wouldn't have bought the 250ex in the first place i would have bought a even a 300ex over that but my recommendation to you is buy a 400ex i'm 15 and this spring i'm gonna buy a 400ex hopfully i'll have the money

 

No offense, but what the heck are you talking about? I have a simple question....regardless of what bike I have, if you install a new aftermarket K & N filter...do you have to do anything additional? Anyone over 15 care to respond? And by the way...how the heck does a 15 year old afford a new 400 ex anyway. Some of us don't have 5 grand laying around, we buy what we can afford geez.

 

K & N yeah...not M...but if you look on your keyboard, the M is next to the N. Easy mistake.

 

you did it twice. and no there isn't anything additional you have to do. but i'm sure you don't care what i have tosay cause i'm 15! and i never said anything about my 400ex being new.

 

K&N with Outerwears and vent the airbox lid unless you are running in wet/muddy conditions. Look at the opening at the end of your snorkle.....it is the size of a nickel and is the limiting factor in your airflow!! I also run an FMF MegaMaxII, and it perks the little bike up pretty good.

Yes you will need to rejet. The point is to get more air into the engine, and that will also require more fuel. If you don't need to rejet, then there was no point in doing the mods in the first place. Running lean is dangerous for your engine!!

 

A good double foam filter like Uni breathes very nearly as well as K&N, and keeps fine dust out of your cylinder. More particles get through a K&N, shortening engine life. Outerwears makes a fabric airbox lid replacement for the 250ex. We run that, and it woke up our ex noticeably. Then you just keep the foam filter clean, and take the factory airbox lid with you if you want to ride in deep water. Had to rejet because more air leaned the mix.

 

Not raining on your parade or anything, I totally agree with you about your quad. Who cares what you got as long as you got something. I'd rather have a 250ex rather than nothing at all. But, an easy mistake? You can just say you thought it was M, very unlikely that you made the same typo 3 times. But yeah changing your filter will give you more power. therushnkid just lay off already, who are you to judge what others ride?

If you get the 250ex peppy enough that thing is a wheelie machine

 

Whats up your butt therushnkid? He didn't ask if he was interested in a 400ex. No need for the extra comments there.
Do like scosho and speedy said and that 250 will be a "wheelie machine".

 

Serious...I knew it was K & N...but I have taken a few blows to the head playing ball....maybe I am just loosing a few brain cells.