I have had a K&N filter on my sportbike with good performance results and would get one for my cars and Suzuki Eiger 400 but I recently have heard that these filters do not do a good job filtering the air, which results in increased likelihood of small particles entering the motor and causing damage (see link: http://members.aol.com/brnorth5/amsoil/airfil.htm). This would be particularly bad in an ATV engine, being around dirt more often than a sportbike. Also, not good for automotive applications (100,000 miles of exposure instead of 5,000 or so on an ATV and maybe 30,000 on my GSXR750). What has been your experience/opinions using the K&N vs Stock?

 

I personally am a huge K&N fan! I have one on all of my quads, my car and everything else that has a motor. On the off road applications you should get an outerware to go over the filter, that catches the small particles your mentioning. On the car I don't use anything over the filter and it hangs down right in front of the radiator. I have been running this setup for a while and have had no problems (the car is a 400hp twin turbo nissan). Hope this helps![img]i/expressions/face-icon-small-cool.gif[/img]

 

The people that do not like a K&N filter because they let dirt in are the people that don't service them properly. A K&N filter is easier to service than a foam filter and filters just as good as a foam filter (and flows more air),when serviced properly. I have personally used K&N filters on sprint cars and limited sprint cars since 1979 and can honestly say that I never found any evidence of dirt in the Injector stacks or carburetors on a properly serviced air filter. I would recommend using an outerware in extremely dusty conditions , this will extend your service interval a ride or 2. Of course if you are racing you should service your filter after every race.

 

I have a K&N on my Truck and wouldn't dream of putting on on my quad. The truck is driven freeways and around town is serviced/cleaned often, I use lots of their oil. It will allow small dirt particles though. I used some white grease inside the filter on the carb and after 3,000 miles is showed dirt on the grease. You can do the same for your quad. The outerwear will not stop the smaller particles. If you hold the outerwear or any filter up to the sun and you can see though it, dirt can get though it. If I just rode in the mud, maybe a K&N, in Socal it's a talc like dirt that gets everywhere. I use a UNI foam and am looking or making a UNI outerwear for the truck. Read the UNI site for more filter information. Remember nothing is free if it flows better, it can't filter as well, if it filters better, it can't flow.

Smitty

 

I have ds 650 on nitrous and i have more money in this bike than most people have in there vehicle and i run strickly kn products on my bike and i run mainly
at the imperial dune and next year will be my third season. on the same engine.
BUT THERE IS NO SUBSTITUTE FOR MAINTENANCE!!


PS.WE LOST A ENGINE WITH A UNI THIS YEAR!!

 

I was using a uni on my old 400ex. After a long days ride(with no air box lid) there was dirt in the air intake. That filter has never been used again. I switched to a K&N and rode the same conditions, took the filter of NO DIRT. I am sold, you can read all the charts and statistics you want. I think K&N`s are better. I have read you can over oil a K&N. You only want enough on the filter to turn it red. Not dripping off. Dont miss any spots. The oil is what catches the dirt.

 

I ended up rebuilding my engine because of a K&N (without an outerwears or foam wrap) allowing dirt to enter the intake path.

Improper maintenance, my behind [img]i/expressions/face-icon-small-smile.gif[/img]. I service my filters probably more than 99% of the folks on this board. I currently have four stock two stage foam filters oiled with Maxima FAB 1 that I rotate. FAB1 is awesome filter oil, by the way.

Another thing about the claim of improper cleaning intervals - If you read the literature that comes with a K&N filter, K&N themselves recommend you allow dirt to build up to improve the filter's functionality. They also recommend you use an overly heavy saturation of oil for offroad and use a "FilterCharger" - doesn't inspire much confidence does it?

Do this little test and form your own opinion... Hold your filter into the sunlight. Peer into the filter body - if you see light beams passing thru the filter unscathed, what makes you think dirt particles won't pass. BTW, I've seen light thru uni-filters as well.

Also, why do you think top off road engine builders like Curtis Sparks, GT Thunder, CT Racing, and others recommend against K&N filters unless you strictly ride sand, or you run an oiled FOAM filter wrap? I stongly recommend this setup if you insist on running a K&N in dusty off road conditions.

If you run a K&N with a FilterCharger or outerwears, what's the point? You've just negated it's flow advantage over a foamy filter and you still won't capture the smallest particles.

K&N's may be OK for the sand, where the outerwear will keep the sand buildup off the filter while also helping the filter do it's job and where the particles are mostly large (where a stock filter with an outerwears would suffer from relatively poor flow).

There's a big difference between using a K&N on the street and using one for Off Road. Even on a dirt track, the dust levels are very low compared to a typical summer day's ride on an ATV.

Think about this for a moment - why does a K&N flow better? How can it possibly filter better given the reasons it flows better?

Also, I've run timed acceleration tests on a modified 400EX with a fresh K&N (no wrap or outerwears) vs a fresh stock foam filter - guess what - absolutely ZERO difference in ET over numerous runs - also, no jetting differences required.

Don't believe the hype - K&N has a GREAT marketing dept...

I'm fine with a K&N on my truck that sees street use and very little fine dust, I'll NEVER run one on an off road vehicle again.

 

you're absolutley correct,K&N are not the filter setup you need for any conditions in the off road world.and i wouldn't use them in the sand either,sand dust is finer then dirt particles,and are twice as hard.K&N's are overpriced and overrated.

 

Talk to some REAL engine builders , Earl Gaerte , Ron Shaver , Ed Pink , Bob Kriner or Don Ott, They not only use K&N filters on their $40,000 dollar plus race engines , they recommend them . I've seen more dirt on a K&N filter from 1 30 lap race at Eldora than I've seen on some filters from a weeks worth of ATV riding.

Use what ever you want , I have never had ANY problems with a K&N .

 

Hmm... Those "Real" engine builders don't build off road ATV engines, do they? How often are those $40k engine re-ringed?

Again, I've never encountered the dust at a circle track event that I've encountered out on the trail, or racing behind someone on a cross country course in mid summer... Heck, no one would go to a circle track event if the dust levels were like they are at an XC ATV race, or a dry trail ride with several riders.

Dirt, at a circle track event yes - thick clouds of dust, no.... a K&N may be fine for those applications, however, in my experience, and others (like the engine builders I've mentioned) that have decades of ATV racing under their belts - K&N's don't work well unless supplemented.

Just because the a filter may work well in one application, doesn't by any means, make it the universal filter that works best in ALL applications.

You can choose to run whatever you like as well, but there are a LOT of folks here that have had trouble with K&N's passing dust - as well as ATV experts all over the country. Trust that your dirttrack experiences cross over to atving if you like, but personally, I prefer to trust my own atving experience & the ATV racing experience of others. Maybe dust isn't a problem in your area, but it sure is in mine.

Also, no one that promotes K&N filters has ever been able to explain to me why I can see daylight thru my brand new, oiled K&N but it won't pass dust. We're not talking micron filtration if you can visibly see thru the filter....