How of you guys are using K&N Filters

[Psychoone]

I just put a K&N filter in my 2003 YZ450F and notice even more improvement with engine response due to more airflow. However, it seems the seal between the filter and the airbox could be real prone to allowing dirt and sand to get into the engine even with a huge swath of grease to complete the seal. Does anyone have any experience with this?

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2003 YZ 450

2003 WR 450

2006 KFX400

[SSpeeDEMONSS]

i have one and it seems like the seal is fine on mine. haven't had any problems in the 9 or so months that ive had it. i just need to get an outerwear.

[flintlock28]

I personally love K & N filters for normal street use.......but I would be hesitant to run one in the dirt. There have been a number of people on TT that said that it seemed the K & N's were allowing more dirt into the carb/engine. Again I only have street usage with K & N, but I would be hesitant to use in the dirt.

[SSpeeDEMONSS]

several of my friends run K&Ns and one of them has been using them for 2-3 years, with no problems.

[Dolce_Grappa]

I've been running for the last 6 months, however i recently noticed that the weight of the K&N Filter causes the snorkel, going to the carb, to rub. Probably no big deal if your frame is smooth, but i had my frame silver vein powder coated. Basically textured, silver beneath black, way cool. I've tried adjusting the carb and airbox position for a slight air gap, very slight gap. If my sub-frame is bent, i won't find out till its really bent and i replace it.

[Psychoone]

Another thing, I contacted K&N to see if they would make the extreme filter for the YZ, similar to the CRF. They emailed me about a week ago with the new part number.

http://www.knfilters.com/search/product.aspx?Prod=YA-4098-1

These things are cool.

Psychoone

[642MX]

I just put a K&N filter in my 2003 YZ450F and notice even more improvement with engine response due to more airflow. However, it seems the seal between the filter and the airbox could be real prone to allowing dirt and sand to get into the engine even with a huge swath of grease to complete the seal. Does anyone have any experience with this?

Pro Seal makes a rubber type of seal that stays on your airbox. I've been using the Pro Seal for awhile now and really like it.

[aedwards07]

I am getting 2 of the Xstream ones for free from K&N for contigency.I will let you know how I like them.I currently have TwinAir filters.

[amsoilmark]

if you check all the facts K&n filters are fine for street use and do have more air flow than some others, but for dirt use K&N recommends using a oiled foam overwrap.. the gauze does not stop all the dirt by itself

[mxmark]

Hi, I have seen some Warranty claims denided from using this style of filter. Thanks Mark

[Psychoone]

I think I am way past the warranty for my bike. Besides, Yamaha as all manufacturers will do whatever they can to get out of paying for factory defects, (ie woodruff key), but good point.

[BoosaDan]

Considering a K&N here, for my '06 YZ250F. Do they make an outerwear for this shape K&N? I probably wouldn't run the K&N without the outerwear, I had a K&N on my Raptor and yes it will allow "some" dust through, but with the outerwear the dust is significantly reduced. Just curious.. Thanks everyone!

[King_Air]

Considering a K&N here, for my '06 YZ250F. Do they make an outerwear for this shape K&N? I probably wouldn't run the K&N without the outerwear, I had a K&N on my Raptor and yes it will allow "some" dust through, but with the outerwear the dust is significantly reduced. Just curious.. Thanks everyone!

Hey it's yuur engine, but on my engine I want the dust eliminated, not significantly reduced. If you have to put a foam outerwear, why not run a foam filter and be done with it? Again just my 2 cents. BTW I also used K&N on street applications, but not off road.

[yz426em]

I used one a couple of years back on my 426, and i will never use one on a mx bike again. I would ride about a hour and the filter would be packed with dirt to the point that you couldn't see the "fins" and when a k&n gets that dirty cleaning is a pain. I will stick to my twin airs for know, the seal is perfect and cleaning is a breeze.

[WB450]

I used one on my 1984 XR 350, but NO WAY on my 07 YZ 450. I don't think they stop enough dirt for my satisfaction. Twin Air in my bike.

[BoosaDan]

Yeah you are right... I found some other threads after changing my search from "outerwear" to "precharger" and found a lot of people saying exactly what you just said. So, I'll have to go with a No-Toil or something. Thanks.

[grayracer513]

The issue with K&N filters is and has been this:

Pro:

> Per Square inch, they flow more air.

> When correctly oiled, they filter better.

Con:

> Some early dirt bike filters did not have enough media surface for good air flow.

> They clog faster.

> This is the biggest problem: They are so much more difficult to properly and thoroughly oil that most people don't do it, even when the think they do, and the result is that the under oiled filter doesn't filter well at all.

[runester]

I am currently running a K&N on my 07 yz450...I have the rubber seal, it actually came with the filter and I have a pre charger, which is just a nylon wrap (harder that sh_t to install BTW) so, rubber seal, grease, precharger, well oiled (uniform in the folds...EASY to over do it!! Careful if you get one) Anyway, I FOUND DIRT IN THE SNORKEL LAST WEEK!!!!! I was amazed, I have been using these filters on all my bikes for yrs and this is the first time, was not pretty either, chunky dirt my friends, I was in barstow (Ca mojave dessert town) about two weeks back the first and LAST trail this bike will be on, anyway hit a DEEP silt patch about 100 ft long and I am pretty sure that s what did it, I have only got about 16 hrs on the bike and the filter has been on for about 14 of those, I've cleaned it 5 times and this was the first time I found dirt, I think the oil kinda clumped up the silt, anyway, I really inspected the fitting after that and even though the rubber seal fits perfectly around the snorkel collar after alot of tweeking and squeezing my fingers down into the box I am now positive that the shape of the filter is off..it sits a bit wide at the corner on the bottom which is a sort of sharp corner. I have the "extreme" that was mentioned and linked on this post. So, do yourself a favor, before you install it check the fitment and if it is like mine, stick the seal wide, id say about 6 mm out from the seam of the snorkel collar, also of you use the red K&N spray oil GO LITE, or you will have a red puddle to clean up, as well let it set out for an hr or so before you install it after oiling if you use the red K&L oil

[felix 222]

uni kit here

[dirtworld]

i dont have any problem with the xstream, i put it on my 07 yz250f 3 days after i got it brand new.

i also have 12 uni-vent filters in my airbox. i cleaned out my carb last week, after a year and a half of riding and probably well over 160 hours on my bike. i found it was quite clean to my surprise, there was a bit of dust residue or something in the bottom of the carb, but other than that it was very clean..

with k&n's, to keep out the dust and dirt its more of how you take care of them, how you install them, what kind of bike you put them on, and if they fit correctly. i think my bike would be proof of that statement especially looking at the condition of my engine..

and they are so much easier to clean than a normal air filter.