Air Filter

[The Ox]

I am going to post this here because I am looking for a pros opinion on this subject. I have ran sleds, atvs, and dirtbikes for most of my life. I am not a kid so I am not new to the game. I currently have kfx 400 and a sportsman 500. They both have K&N filters with prefilters. I maintain them great and clean the filters regularily. Now the question is this, a guy I know was bought a Outlaw Predator, and he was told by 2 different techs at the dealer not to use the K&N because. They said they are just bad, and when they get a motor that is blown or puffing oil, they had a K&N.
So is there any really proof to K&N being bad, or not as good. They have a good reputation, but this is not the first time I heard this comment. I have not had problems yet. I just am looking for some solid evidence to this statement. Thanks

 

[pittboss45]

I can not agree more with the advice that you were given. I had to rebuild one of our engines 3 weeks in a row due to those filters. We were running the K & N with a pre filter sock on it AND the Outer Wears cover on our airbox and went thur 3 pistons and bores in 3 races. We were starting to question all sorts of things that could have gone wrong.

We found out that the air filter was letting dust particles into the carb and that is what was ruining the pistons. We had to look closely into the indentations of the back of the carb to find it but it was there.

Once we changed back to the Uni Filter all the problems went away. We found out that others had experienced the same problems after the motor started to finish races and we told them what had happened.

I would only run a K&N filter on my car, truck or street bike. I will never run one on something that will encounter dirty surroundings. That is also the reason that we will not sell that filter with one of our air boxes.

 

[Awk08]

do a google search for "uni filter vs. k&n", and the evidence is there also, that yeah, the k&n's allow more air to flow, and also more dirt to pass thru them, and i have heard that none of the guys who run in sand or the dunes run them, cause sand will eat sh*t up way quicker than just dirt
k&n's are garbage imo!!!!
uni filters rule!!!!!

 

[phragle]

Uni's filter at a much finer micron level. Also when Paul Leary flowbenched them, the K&N did flow better, but the difference was negligble. He also tested a dry uni,and compared it to one that was well beyond oiled. the difference in CFM was less than 1. In english this means that you can and should oil the hell out of a uni and it wont hurt performance at all.

 

[stephen12091985]

i also went from a k&n to a uni cuz the k&n was letting dirt thru into the carb

 

[brandoz28]

there was a guy on here a while back that was finding sand in his intake tract with a k&n filter. also, use real air filter oil too, regular engine oil can allow small particles to get through, i was recommended PJ1 air filter oil

 

[tyler1blaster]

UNI FTW!!! i run uni's on all of my bikes and they kick ass. k&n's are a ripoff in my opinion. i was running a k&n on my honda and it would always stall out when going through puddles. it was letting water in. my uni doesn't have that problem. ^^^^ PJ1 is the good stuff. i always oil up with that

 

[yzrider]

i have use k&n for life and have had no problems, no dirt coming thru what so ever, it works great for me, but i'm not gonna post any more cause this thread is just begging to be a war...... again

 

[The Ox]

This is all good info. This is not meant to be a war. I too have not had a problem. I run in sandy areas and have rode a lot. I use K&N with prefilter and use K&N oil to oil it. But that does not mean that it is better. Just concerned and looking for hard core facts. Maybe the conditions I drive in are worse or better than some. My wife is usually behind my useing the same setup so that concerns me too.

 

[Awk08]

Uni's filter at a much finer micron level. Also when Paul Leary flowbenched them, the K&N did flow better, but the difference was negligble. He also tested a dry uni,and compared it to one that was well beyond oiled. the difference in CFM was less than 1. In english this means that you can and should oil the hell out of a uni and it wont hurt performance at all.

/\/\/\/\ thats some good info, phrag's, have some reps

 

[Kennedy_Power]

Uni's filter at a much finer micron level. Also when Paul Leary flowbenched them, the K&N did flow better, but the difference was negligble. He also tested a dry uni,and compared it to one that was well beyond oiled. the difference in CFM was less than 1. In english this means that you can and should oil the hell out of a uni and it wont hurt performance at all.

Great information, I have never done a flow bench comparison between the two. I am surprised by the less than 1% difference, but I will believe it. This thread has got my very interested in doing some homework. I know for a fact that my sand drag quads do get some sand in them by using the K and N filters...

 

[The Ox]

So looking at the Uni Filter web site, does anyone have an experienced opinion about the UNi slip on pre filter. I see that you can buy one that goes over the K&N and acts like a pre filter. It would be cheaper than dumping all my filters and buying new. Just wondering if it is effective.

 

[UniRacing]

<- Uni is the way to go!

 

[phragle]

So looking at the Uni Filter web site, does anyone have an experienced opinion about the UNi slip on pre filter. I see that you can buy one that goes over the K&N and acts like a pre filter. It would be cheaper than dumping all my filters and buying new. Just wondering if it is effective.

Actually I prefer uni's older design, their old design was 2 piece, it contaned the inner foam element that was oiled and the outer prefilter. now they seem to be selling them seperate

 

[Awk08]

the ones i have recently gotten are 2 piece, an inner yellow, tighter foam, and a outer red, more open celled foam, is this the 2 piece mentioned???

 

[phragle]

may be... I use 250r uni's so I havent seen a blaster one in years..