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rnrdozer

K&N airfilter

24 posts in this topic

I have a XR650R and put in a K&N airfilter which was recommended by the local motorcycle shop. then I was told that the K&N was'nt a good idea because it let too much air in and could allow some fine dust in the motor. Anyone have any experience with this? Thanks, Rich

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Ive heard a lot of bad things about the K&N filter when it comes to dust. They work great in Supermoto situtations because they flow pretty good when they're clean. But when the going gets nasty, a nice foam dual element filter is the way to go.

If you dont have a lot of experience with this stuff, youve really got to keep an eye on the advice that comes out of bike shops selling aftermarket stuff. Some is great, some is down right criminally bad.

If you were simply buzzing up and down the freeway, the K&N would be great. But if you flog the thing in the dunes...no bueno...

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dont use it off road esp. in real dusty conditions, so ot off road at all. I use one on my 4x4 for street driving and keep a fram paper filter or off roading they filter way better!

I also had one on my old 600 and noticed too much silt in the air box after my 1st ride on it, got a foam filter right away...

not worth riskin it in my opinion

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I agree with miguelitro. The K&N flows well, but it lets in fine dust. I always found a fine layer on the inside walls of my airbox. Now I only use it after it rains when there is very little dust. Needless to say, I haven't used it in a while. I prefer the UNI twin foam.

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There has been a lot of talk about K&N letting dust through. I had one on a 4 wheeler and it did let dust through. I use UNI on all of my bikes. :banghead:

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Almost all of my buds that I ride with that use aftermarket filters use UNI. I ran a K&N in my street bike for a long time and they do flow great, but that lower restriction came at the price of a very porous element. I ride a lot in silt and sand, as do the people I ride with and they steer clear of K&N. Backed with the posts in this and other boards, it sounds like the concensus is against them.

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To add to this, the stock filter element from Honda is a very good part. Neither the Uni nor TwinAir are any better in any aspect. Except maybe price when its time to replace it...

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hmmm, i don't have a K&N on any bikes but i do have one on my truck and i thought as long as you kept it oiled you were fine...huh... the directions also say that "grime" helps to filter out more stuff... must just be K&N blowing smoke. :banghead:

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hmmm, i don't have a K&N on any bikes but i do have one on my truck and i thought as long as you kept it oiled you were fine...huh... the directions also say that "grime" helps to filter out more stuff... must just be K&N blowing smoke. :banghead:

The normal fine road grime will actually help, but its also on its way to being plugged at that point too... :banghead:

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I don't think K&N filters can universally be classified as being all good or all bad, etc, because they're not all created equal and the same goes for any filter. In terms of filtering, I think with some effort that most people can determine if their air filter has issues. I've had both good and bad K&N experiences, but I've chosen not to use K&N anymore for our off road needs. Here are some pictures from yet another K&N experience I just had earlier this year. The pictures are of the inside air boot that feeds the throttle body on a 97 Ford F250 5.4 triton powered 4X4 truck. The air at this point should be 'very' clean and there's really no wrong way to install this air filter since its cone shape is self centering in the airbox. I didn’t take any pictures of the air filter itself, but it looked freshly serviced and clean since it was last serviced less than 10K miles from when these pictures were taken. Here are two pictures to check out…

Picture of the intake feeding the throttle body

One of the paper towels used to wipe out the intake

In the past, I've seen the same dirty intakes in our diesel trucks and in our long travel dual sport buggy that we used to have. I'm sure they're a good enougn filter in some environments, but I've had better particulate filtering results with OEM filters in dusty environments. K&N finally redesigned the air filter for our diesels and the issue of dust appearing inside the airboot was finally resolved with a redesigned air filter, but it took a long time for this to happen.

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To add to this, the stock filter element from Honda is a very good part. Neither the Uni nor TwinAir are any better in any aspect. Except maybe price when its time to replace it...

Correct, the OEM Honda filter is very good. In fact, the foam is more dense than the UNI and probably filters better. However, there is less flow because of it.

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Correct, the OEM Honda filter is very good. In fact, the foam is more dense than the UNI and probably filters better. However, there is less flow because of it.

It cant be too bad, the best CRF engine builder in the country is making 60+ horsepower with the OEM filter AND THE BACKFIRE SCREEN IN PLACE.

Oh ya, one thing, thats a stock bore 450cc CRF.

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The normal fine road grime will actually help, but its also on its way to being plugged at that point too... :banghead:

oh i know..i've been cleaning mine almost every oil change...but i haven't had it very long...i also didn't notice much differance in power but the filter was only like $15 more than my reg foam that i would have to replace instead of clean so i opted for K&N

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K&N's have a steep curve on flow...High flow when perfectly clean but the curve steepens quickly once a little dirty where a Foam filter is a more gradual curve...not as full flow as K&N's but it doesn't take much dirt before the Foam out filters the K&N filters. Don't use K&N for Motorcycles off road. and if you use one on a truck that does go off road use a Foam pre-filter and it catches most stuff and lets K&N stay at its higher flow curve longer.

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I don't know where everybody is getting their information, but K&N claims that the filter ouflow foam even when dirty. As far as how much dirt gets by, I have yet to see any credible information on this even after doing a lot of research.

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For our bikes just take out the filter and wipe the air box and then check it after a ride. if it stays clean use it...then chose what ever filter you like that keeps the air box clean.

I have a white brothers that has served me well...I'm going to go Uni with internal screen next though

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In a former life i raced a bit on 3-wheeler's yeah yeah, im old. big deal. I ran a K&N on my '86 200X and it worked very well, with a filter skin on it. if i didnt pre-filter it, the carb sucked alot of crud and caused me problems. using the pre-filter wasnt a huge issue for a 5 min. track race, just yanked it off and threw on a new one. for extended riding? i'd try something different.

*just my 2cents*

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To add to this, the stock filter element from Honda is a very good part. Neither the Uni nor TwinAir are any better in any aspect. Except maybe price when its time to replace it...

I would say the Honda paper filter would give the very best protection

for fine grit. I am sticking with the paper filter in my L for that very reason.

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K&N makes a foam "prefilter" you can slap on your normal one that cuts out the "dust" issue. I've used them on sandrails/desert trucks and they work fine. Not that I've ever noticed dust going through anyway. Take it off when you get back on the street to open things up a bit.

The whole point of the "oil" is to make dust and particles stick to the element, and yeah grease and fumes that you suck up will attract more of that stuff, so that's where they get the claim it cleans better. Up to a point, anyway.

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