Air Filters

[B.C.#11TRX400EX]

Whats the best air filter K&N, UNI, Twin Air? or what? Ive been looking into getting a K&N filter, IM gonna be racing XC if that helps any

[ridehonda400ex]

K&N are great filters, flow VERY good but most importantly CLEAN AND OIL them properly! Use the recharge kit that you can buy. And use an outerwears if you want. I dont but I clean mine frequently. Foam filters such as Uni are also great i have used UNI and twin air. Both are good but i prefer my K&N

[chronicsmoke]

You'll find alot of hatred towards K&N for 'passing too much dust', which is true if you dont maintain your filter.. If you regularly clean your K&N and use an Outerwears pre-filter then you should be good to go.

I like UNI myself, both for the price and simplecity. But all the options you mentioned are reputable companies that will work great if the proper care is taken..

[B.C.#11TRX400EX]

thanks guys

[CJM]

Im happy with the uni.

[atvextremerider]

i have an k/n and i love it great power gain

[Stickman400]

I also run the K&N and I love it. I was always told that they are garbage if you run them without an outerwear in dusty conditions. I'd be sure to get an outerwear if you buy one, unless you like cleaning it after every other ride or so.

[hellshot00]

i run a K&n and i love it i also do alot of woods riding and dusty conditions and never had a problem with it oh i also run the outterwear cover

[Honda#4]

I run the white bros powerfilter (foam style) they use to make with a EHS lid and I couldn't be happier.

[B.C.#11TRX400EX]

yep then i think im gonna get a K&N filter with a outerwears wrap

[ridehonda400ex]

Also, i dont run outerwears and have 0 problems at all. But i frequently clean mine, i just cleaned it this morning actually.

[B.C.#11TRX400EX]

o yeah wat type of oil do u put on the filters after u clean it

[ridehonda400ex]

http://www.partsforatvs.com/default.asp?p=366&c=208&cn=Maintenance


^that is everything you need, ONLY USE THIS KIT, do not use foam filter oil or motor oil. This is a kit with a big cleaner bottle which is worth it.

[slightlybent47]

Everyone has an opinion on the filters and here is mine.

If you plan on rebuilding your motor on a regular basis then by all means use the K&N.
You have to realize that ATV racing is done on a curse that is filled with fine dust and the K&N filter is just not the type of filter you want to use in this application.
Yes they flow great and much better then a stock foam filter and do great where fine dust is not a problem.

Trust me when I say that the extra HP that you (MAY) get with the K&N is not going to win you any races. The deference in HP between a stock foam filter compared to no filter at all is minimal at best, and some test have been done to prove it. You get maybe ½ HP gain over the stock filter.

These high performance ATV engines can’t deal with any kind of dust or dirt getting in the intake and will chew themselves up if it does.

Your choice, minimal HP gain vs. reliability. You make the call.

[CJM]

I think the only saving grace of a KN filter is an outwears cover-which imho negates any small benefits you get from using a KN filter seeing as it flows more.

I have an outwears box lid and my uni. I generally ride in sand and its DUSTY. I gotta clean the filter every 2-3 rides as is covered in dust. Maybe a full lid would help, all I know is I wash it with some gas and spray it up with some PJ1 foam filter oil and its dirty in a few rides-enough that you can see the sandy dust on it and that means its doing its job.

[B.C.#11TRX400EX]

so wat would be the best choice for XC?

[CJM]

Personally a UNI is. Like I said, a KN is imho really only useable with an outwears filter on it-which means it doesnt flow as much as it should and thus you dont get squat from it.

Honestly the stock filters fine, a unit might flow slightly better and a KN slightly more than that if it doesnt have a pre filter on it. I only got a UNI b/c my stock filter was absolutely shot and split apart (although I ran it like that for eons lol). Was it truly stock I cant tell for sure-it mighta been a uni-was beyond repair lol.

[slightlybent47]

I use the stock foam filter; witch is a 3 layer filter, with an outer filter over that.
The outer filter has much larger wholes in it then the stock filter and is there just to keep the bigger stuff out. I also use bel ray foam filter oil witch is water resistant and very sticky and wont migrate to the bottom of the filter like motor oil will.
I run with the snorkel removed and the lid removed as well so I need better protection.The oil is the key to a filter working it’s best.
There’s a reason the manufacture puts foam filters on there equipment. It does what it’s designed to do.

Like I said before that little bit of gain you get with a deferent filter, wont win you any races, At least in this application. . Stay with the foam filter and you wont be sorry.