I wanted one so bad for my bike because it is a little rich now. Put i can't evan ride with one. People say it lets in to much dirt, im not sure. What do you say? And just so you know its a 2009 klx250s with a full pipe.

 

i just bought a twinair for 27 bucks through my dealer

 

I got my K&N for my 250s through JC Motors for $45

Run it on your bike. I know a lot of people say that foam works better for dirt use but I don't know. The kandn on my bike is perfectly fine after 600 miles with on and off road use. There isn't much dirt at all in the air box and I rode down plenty of dusty roads.

I have an open KandN ( meaning exposed in the engine bay, no air box ) on my Chevy Tahoe and I have had it for 20,000 miles and it works just fine. Not dust coated or anything.

Just take it off and blow it out and clean every once in a while.

 

Foam is the best if you do off road or ride in a lot of dust. K&N has high flow, but high flow is achieved with less filtration capacity. Dirt trackers do them, but if you notice on dusty tracks they put on the foam socks made for them.

Virtually no motocrossers and off road motorcycle racers use them except the flat trackers and even some of them won't. The ones that don't tear down their bikes like the pros do between events or relatively frequently.

If you're doing road use, K&N works fine, otherwise stay with a foam filter and jet your bike if you need to lean it out. I'd use one in my road bike, but no way on the KLX650. I got a Uni filter to replace the worn stock one... after 15 years with the stock one. Don't get wrapped up in the K&N hype. The only place they pick up any power if they do is on top end where flow MIGHT be restricted. Again... great on road, bad off road.

 

My bike came with one and I took it out for the summer dusty riding. If I was always leading the group or riding by myself i wouldn't have worried too much about it. I've noticed how clean any of my filters stay when I'm the guy leading a ride.

The K&N does for sure breathe better, like 2-4 jet sizes bigger over aftermarket or stock oiled foam. I noticed this right off when I was working on jetting. So for a SM or street only riden bike I thinks it's a good mod along with jetting for it.

Never tried it, but have thought of oiling the k&n with tackier oil (anyone try this?) They say not too, but they want to sell their oil, and want the advertised flow increase. Don't see why it wouldn't work.

If you want to freak out, hold a K&N or a new unoiled foam filter up to the sunlight. You wonder how it filters anything! Now oil them both and try it again. The oiled foam lets a lot less light through, the K&N doesn't seem to change much.

OK, one more rant, sorry. K&N filters became popular in off road desert racing not because being a good dust filter, but because the dust would load up on them and they's still flow decent air. In racing you don't want to stop to change a fine foam or paper filter and lose valuable time. Also a clogging filter means your putting your foot into it more to make the same power, which increases fuel consumption.

 

For whatever its worth:

http://members.shaw.ca/volkswagen/****er/****ER.htm


After reading this, i would never run a K&N filter personally. But thats just my two pennies.

*edit*


Okay forum displays S p i c e r as a bad word ?

http://members.shaw.ca/volkswagen/S p i c e r/S P I C E R.htm

Use that URL and take the spaces out from between the letters in S P I C E R

 

I've been running them for years and is one of the first mods I do on all my bikes.

 

I'd never run one on a dirt bike. As said above, there's a reason why mx'ers and enduro's don't use em. Not saying that's the right way to go, just my 2 bits.

 

Have put K&N's in every bike, ATV, and car I've ever owned. My current ATV has had one on it since 1999 so of course it sees no pavement, all dirt. Zero issues in 11 years. Put a K&N in there and move on to something else.

Ryan

 

opinions are like... armpits... everyone has them... some stink more than others

Mine would be that if your goal is to lean the bike, pull your snorkel, or your lid, use a cheaper filter that protects your motor, like the twin air rather than dump money into a very pricey filter on a bike that may see things like mud, water, and extreme dust inside the airbox (mind you if you never see dust, mud, or water, that may be a mute issue to you). On a car I love a K&N, on a dual sport bike, I'm not sure which armpit smells better to me.

Also - I did read the link posted above, It was definitely not a ringing endorsement of K&N and the data I think was as fair as data can be. The commentator did write that he didn't think K&N helps stock motors at all, however I think higher revving stock engines can be helped breath better at the top end with a higher-flow filter, and of course I also think this is a trade off in dirt trapping efficiency. My old prelude got an easy 800-rpm more out of shift points in 2nd-4th using a K&N filter over a generic paper one, I was happy with it, and it lasted the life of the car... which wasn't that long...