hello to all! ok so my question today is for my atv filter... i ride a 400 ex and i was wondering what kind of air filter i shoudl use? a K an N style with a outerwere or a foam filter with a foam cover(kinda like an outerwere)? i ride in some very dusty areas with no water but some mudy areas when the rain comes along... so wich filter setup should i run? i want to also run an open airbox with no lid so if that effects the desision on K an N or foam filter? thanks help me out!

in very dusty conditions, an oiled foam filter is best IMO.

but... a K&N is much easier to clean.

so... If you don't like cleaning your foam filter, witch is a PITA... it might be good to go with the K&N...

I guess it's better to run a clean K&N than a filthy foam filter. Same reason alot of my friends went with K&N's.

uni all the way

x2. i wouldn't trust a k&n filter. not on an atv anyways.. when we bought my wifes 450r that's what was on it.. and when i got it home and took it off, the intake boot leading to the carb was covered in dust and had some grains of sand in it.. and if that's going through the filter you know some of it's going in the motor,and that kinda stuff wears down motors quicker than ya think.. i run a uni-filter and every time i take it off to clean it, there isn't anything in the intake tube. it's spotless.. and as far as foa, filters being a pita.. get som no-toil filter treatment and cleaner. you can get both bottles in a kit.. use them together and it takes just as little if not less time to clean than a k&n.. jmo

Foam...
My bro uses a k&n and there is no performance differences between his bike and mine. I'm still running factory descreened filters with Notoil. I just snagged his after he switched so I have two and keep one as a backup. I have a k&n on my ex and sand is still getting thru, even with the outerwears. Somehow it gets under the elastic band and into the filter so it gets cleaned almost every ride, very annoying. A friend lost his top end from the fines getting thru his k&n although I doubt he cleaned it every few rides.

yup.... i still run the factory air filters.

When I bought my R, I ordered two more OEM's on ebay... so now I have three... I just oil one of them up before I put it on and keep the dirty ones in a plastic bag until I run out... then clean them all at once.

It's not as much of a PITA that way....

And I also use a spray on oil instead of the one in a bottle. Waaaaay easier.

it is proven that K/N have better flow than foam filters. But this is at the expense of letting some fine particles get through that the foam filter would normally catch. If you ride at the dunes then the K/N with an outerwear is your best bet, no airbox lid; max flow. If you ride in the dirt, dust, mud etc (particles finer than sand) then I would use a foam filter. Uni foam filters have alot of flow for a foam filter and still catch all the really fine particles

my question is. do they make a foam filter for the rotax ron woods free flow intake tube? Overall Diameter = 2.5" . I would like a foamer for dirt riding...

foam...unlike the k&n you can clean it by hand so way cleaner...k&n will always still have some trash in it

If your riding strictly sand then k&n style with outwear but anything else foam unless your only riding on pavement maybe lol.

I run a K&N on my 250R, no outerwear. Dirt and dusty trails. It was getting dirting so took it off
to clean. Did the white glove inspection, clean, no particles. I love the K&N.

I do this everytime I clean mine also and I've never had anything on the rag. People are not cleaning them enough and/or properly if they are getting a bunch of junk in the intake tube.

UNI ONLY!! Sand, dust, mud, whatever! If you run a K&N you will be constantly rebuilding your motor! They are useless!

Agreed!

UNI is definately cheaper... Replacement K/N filter for my RonWoods intake is $55 from K/N. The UNI Foam Replacement in the same size is $20... I'm gonna go foam this winter for trail riding, I'll report any loss of power if there is any

x2 Never had an issue with my K & N. Just keep it clean and oil it after you clean it.

Here is a test I did comparing K&N with and without a pre filter and a Foam with and with out a cover

I'm not arguing the fact that the foam flows almost as much air but when all you do is sand ride like me the foam filters are a nightmare to clean when they are completely caked with sand and eventually that sand works it's way through the filter. I can clean my r&d filter which is same as k&n only more layers so it should filter even better in I'd say half the amount of time probably more than half like 1 3rd the amount of time and with the outerwear on there no sand at all sticks to it the actual filter doesn't even look dirty when you remove the outwear but I clean it every 2 to 3 rides so it never really has a chance to get dirty.

anyone run the Velocity Air Filter?

I think the foam filters works the best in any way

UNI all the way K&N not so good