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View Full Version : Confused on Air Filter Setups!



Big D KC
03-09-2009, 01:34 PM
Ok, first off forgive me! I know this comes up all the time! However my questions are a bit different then the normal fare of air filter questions. I've been searching for the last couple hours trying various wording but not coming up with much! (that 3 character minimum on a search string is a real pain in the ***!)

Anyway, here is what I am trying to figure out:

After riding the 400ex for the first time this weekend, I went to wash off the mud and got to get a good a look at the airbox/air filter setup the previous owner had hacked up. I'm not impressed at all to say the least.

Looks like he was running a White Brothers foam filter over the stock wire core. Both of these are trashed on the underside for some reason. (I couldn't see the damage by just removing the air box lid prior to purchase).

So now I need to replace this setup! I do want to run a dual stage foam filter. So now I have options! Looks like some people favor getting rid of the restrictive metal core in the stock air filter. Great! One less part to buy, but what do you replace it with???

I see Twin-Air has a very pricey but complete kit for sale that gives you a mounting point that bolts to the air box, has a wire frame skeleton and then the air filter. This looks like a nice complete setup, but at almost $200 its rather pricey!!
Twin Air Kit (http://shop.twinairusa.com/scripts/silverware.exe/moreinfo@d:/elevclients/twinairusa/ELEVATOR.FXP?item=TA150921C)

So then I look at the UNI filter's and they don't come with anything other then the filter itself that I can see for about $25 Does this filter have its own internal wire/mesh core for structure? Or is it designed to re-use the factory core?

Same thing for No-Toil, looks like just a foam filter no core.

Then you have the Pro-Flow kit from Pro Design, it comes with a filter, a pre-filter of sorts, and a billet collar to mount up with. Same question is it internally supported? Obviously the collar is to mount with, im guessing one end goes in the carb snorkel through the side of the air box, then the other end you mount to the filter.. But what about internal support?
Pro Design Pro-Flow Kit (http://www.prodesignracing.com/trx400ex_pro_flow.htm)

I'm just trying to figure this out! I am guessing you want some sort of support inside the foam filters like the stock setup..?! Maybe this isn't the case..

Remember the internal core of my stock filter is damaged! So it will either need to be replaced with an OEM part, replaced with an aftermarket filter w/ core assembly, or removed entirely. Also remember I am only interested in a Foam filter setup, so no "get a K&N" advice please! ;)

rob_990
03-09-2009, 03:43 PM
i have used a twin air and uni and both mine just used the stock cage so im pretty sure if you just get the filter and not a 200 dollar kit your going to have to go to your dealer or online parts store to get the stock cage for it.

Young_Gun1
03-09-2009, 04:20 PM
my uni came with a cage

03-09-2009, 04:23 PM
Not to jack the thread. But I'm piped, and running a K&N w/ lid. Would it be that big of a difference if i were to remove the lid or switch to a UNI and run no lid? I know the K&N gets more airflow. But it has to be lacking with the lid on. Would I have to re-jet again?

Young_Gun1
03-09-2009, 04:31 PM
doing much of anything to the intake would make a jetting change recommended
i used to have a k&N and i removed the lid but i had to since i plugged up the snorkel hole
i would just prop the lid up on the back clips to let in more air but still have some portection

03-09-2009, 04:43 PM
or just buy an outerwear for the airbox itself

ae13291
03-09-2009, 05:06 PM
i have an outerwares lid with the k&n, it works great with this setup

03-09-2009, 06:42 PM
Im running an outerwears with lid on.

Big D KC
03-09-2009, 09:14 PM
Interesting. So obviously there are two different UNI filters as well.

More fuel on the fire! Anyone else have any experience here??



(And yes, Suicide, you did indeed intend to jack my thread. There are countless other threads you could have posted your questions in. I know because I found quite a few of them while searching for the answers I didn't find to my questions. Nice Job.) :rolleyes:

03-10-2009, 02:17 AM
:p .. yeah I follow all your 17 posts and jack em up.. get real

Big D KC
03-11-2009, 10:15 AM
ummm, ok..? :confused:



Anyway, moving on! Anyone else got any thoughts on the internal filter cage versus no cage deal here? I gotta figure something out and don't want to order the wrong thing! I'd much rather just order the UNI filter for $25 or so, but there are atleast two different versions of this filter it appears. One with cage, one with out..

Do I need a $200 kit or will one of the $25 filters only work?!?