K&N air filter, why do people hate them?

[motopsycho87]

I honestly don't understand it. It seems to stay cleaner, still not let bugger all through, and is so easy to clean! Did a 3 hour enduro in the dustiest conditions I've ever ridden, inside its spotless, outside its minging! Same goes foruddy conditions, big bits seem to fall to the bottom of the airbox rather than stick.

[skippyjlo]

I remember reading a big thread on another forum about the k&n air filters. The consensus was that because the things breath better than other filters that they let micro particles through. I won't claim that I know either way. I just remember the popular opinion was that k&n was better suited to road oriented vehicles.

[webmaster]

They have tests where they pass dust through them and then weigh the filters afterward. The more the filter weighs after - the more it stopped. The less it weighs after - the more dirt went into your engine....

K & N loses big time to any alternative - paper, foam, whatever... On road or off road - doesn't matter. On road you get the other common problem happening - the oil on the filter media is pulled through and "fouls the MAF" - the mass airflow sensor (maf) becomes fouled with oil and doesn't get a good reading.

And given the media they will typically clog much, much faster in extremely dusty conditions when compared to a multi layer foam filter..

My advice - and I will be blunt.....

Throw it in the trash or sell it to someone you really don't like....

Friends don't let friends use a K & N....

jeff

[gasgasman]

When I worked for Ford, I made tons of money from K+N filters.
They let so much dirt through on the diesel engines, turbos would get "dusted".
Totally wasted them. Engine would be next to get destroyed.

[iajim]

Motopycho87 you seem to have found a very polarizing topic. I've used K&N filters in the past and never had any problems. The bikes I used them on were fairly diverse, '76 Can Am flat tracker, '80 Yam. TT 250, '84 Hon. XR 350, '78 Suz. 100 (daughter's bike). Some were run in very wet/muddy conditions others (Can Am) were never run in anything even damp. They are still the filter of choice for most of the dirt track crowd and I know they will not stop water at all. Some foam filters are pretty good at this although my feeling is the filter oil has more effect than the brand of filter. Roadrace or dirt track, K&Ns' seem to be pretty good and in all fairness I've always stuck w/foam filters on my GG300, '92 Husky 250, '04 KDX, and '90 Yam. 180. If you've been using it with good success I wouldn't switch because someone else doesn't like them. Ask some other people who have the exact same bike as you and ride in the same conditions. You'll always find a few "forceful opinions" but use what works for you. Jim.

[Darkside]

is this consensus just for K&N? or for any high flow gauze type filter. because I notice especially in the auto motive industry there are a lot of high flow mfg. now, but I believe K&N was the first

[webmaster]

I will add some "facts" to my opinion - ISO filter test results for various filter media...

http://www.billswebspace.com/AirFilterTest.htm

K & N passes more dirt, clogs more easily and has the lowest filter efficiency....

Like I said, and I won't mince words, do yourself a favor and toss it in the trash...

Jeff

[shang]

Personally, I don't think I would ever run a filter that had polarized opinions. I don't think I've ever heard a complaint about a properly installed foam filter. Lots of complaints out there about K&N though. It's just not worth the risk to my motor and bank account.

[motopsycho87]

All this being said. I sprayed grease inside the airway before I put the filter on to test it. As said, I checked after the dustiest race I've done, and it was spotless. I always got water through from puddles and pressure washing on a foam filter. The problem is they still absorb water no matter how hydrophobic the oil is. And with foam filters I've always had water get through, and bad running after big puddles etc. Admittedly, I've sealed the airbox to rear fender since.


I was dubious, read many reviews, positive and negative, but frankly am very impressed. And with it so easy and cheap to clean and re-oil, I'm definitely keeping it!

[webmaster]

Well, you did ask why people hated them....

jeff