I am currently using a K&n filter witrh outerwear on my 450r, and lately everyone has been knockin them saying not to use them and they shouldnt even be called a filter... I ride at the dunes 20% of the time and mostly desert riding... What do I need to look out for or am I just fine...

 

I run K&N's on virutally everthing I own. On my sand toys, I run a K&N with an outer-wear for many years and I have never had a problem. However, a good friend of mine that is a former Baja 1000 winner and Score over-all -champion bags on them bad. When I was building by buggy (with his help) he completley insisted on running a UMP filter because he had a very strong opinion against K&N's. After building the buggy all my buddys that run K&N's said my filter set up was the best (mostly because it was a better attachment) and wished they had one. The air filter that would have come with my 14K LS2 motor package from the engine builder would have beed a K&N....

I suppose I did not add anything here, but I am curious too.

 

Some people say they let too much dirt in, but I bought a Rubicon off a guy who, let's say, did NOT maintain anything on the machine. It eventually needed a rear end rebuild because of all the sand and mud in the pumpkin and absolutely NO fluid. This thing was pushing 6,000 miles when I got rid of it, and aside from what I just mentioned, I didn't have a single problem with it.....the K&N Air Filter included. And trust me, that thing probably got it's first cleaning in God knows how long when I finally bought the machine off of him (somewhere around 4,500 miles). There is currently a K&N on my King.

 

Any dust that gets through, will absolutely devastate your 450R's valves!

I ran K&N's on everything (that's a lot of rejetting!) for about a year. I serviced them FREQUENTLY (when the Outerwears just started to get moderately dirty). Every time I would wipe the boot out with a white cloth, and there would be a light film of very fine dust. You could rub it between your fingers and feel the grit!

Hold a K&N up to the light. You can see right through it! It is one dimensional. If dust doesn't get caught in that very thin layer, it is going right on through with nothing behind it to back it up!

Then imagine a relatively thick foam filter. If something gets past the top layer, it has another inch of foam where it is going to get caught. The foam filter offers you a safety net, that the K&N just can't give you. I highly recommend the ProDesign (ProFlow) adapter and foam filter (made by UNI) for your R.

The only place I now run a K&N is on my street truck, and then only with a foam warp on it.........

 

I believe there are two situations where a K&N may be appropriate. The first is in clean large particle sand dune areas like Oregon Dunes where you essentially never see a dust cloud regardless of weather conditions. Even then you should run an outerwear prefilter over the K&N. I believe sand dunes like Glamis where the sand is finer and mixed with lots of fine dirt particles that a good foam filter like Twin Air will give much better protection. The second situation where a K&N may be appropriate is in extremely dusty conditions where you expect the air filter to be completely covered with thick dirt AND where you have no opportunity to clean filter AND where getting to finish line as fast as possible without regard to motor damage is the ONLY consideration. K&Ns have a reputation of being able to continue passing sufficient air to keep running long after a conventional foam filter is totally plugged and you are stopped. K&Ns also have a reputation for actually filtering better with a coating of dirt all around filter than when clean and lubed.
For all other situations a properly serviced foam filter will definetly, positively, certainly, absolutely, without question, without fail, (ya get it??) always give better engine protection than a K&N. So the question is how much protection do you really want vrs how much engine performance do you need. This is very similar to the loud exhaust situation where many riders believe they need all the help they can get regardless of the consequences. My advice is run a Twin Air foam, use a good foam specific filter oil, use white grease on all filter mating surfaces, and service filter yourself after every ride. Never trust this to a shop.
Edited this post to add that filter skins over a Twin Air is great way to quickly get the air flowing in dusty conditions for only about $1.50 apiece.

 

That's the problem. The cotton fiber breaks down a little everytime you wash a K&N. No different than a shirt thinning out in the wash. If you're **** about maintenance amd cleaning (and there is absolutely nothing wrong with that), then you're better off with a foam filter. If you're the gas and go type, K&N works pretty good.

My K&N's have work wonderful in sand but I'd be the first to admit in dusty or wet conditions, I'd rather have a Uni. Dusty because they need more frequent cleaning and wet because...well, see above. My $.02.

 

someone posted on here a while back about a filter shoot-out someone did on a durmax diesel. They tested various filters including the stock AC-Delco filter and a K & N, and they tested how well the filter "filtered" and tested the performance of the engine by how well the filter "flowed". The test results were basically this- the ACDelco (the OEM filter) flowed the least, but filtered the most, letting the least amount of dirt through. The K & N however, filtered the least, let the most dirt through of all the filters tested, but had the best flow rate, creating the most power.

it only makes sense-to have more air flow, you just dont filter as much. Sure, they work great for racing, but racing engines are rebuilt after every race, so all they need is power, as long as the engine makes it to the end of the race.

 

Far as I am consender ya K&N maybe a good chose for racing, cause your going to clean it more often and need as much out of your motor as possible. I am a ATV tech in a shop in Minnesota, seen many times they come in and smoking and find a K&N in the air box, packed with dirt and the intake and carb dirty. I don't know why anyone would buy one when a GOOD after marker FOAM filter works just as good and cheaper. If k&n's were so great the manufacitors would already put them in from the start.

 

Thanks for the advise, I am going to stick with the K & N filter for now, I clean it all the time and run an outerwaer so I think i will be okay, plus I am usually out in front of everyone else so dust is minimal haha...