Hey friends, I thought this worth mentioning...
Picked up my brand spanking new KLX in Dec. of 2015. Wanted a new one so I know it's history. Putting on the IMS Pro Series footpegs, I like 'em alot, although the pivot pegs look pretty cool.

Anyhoo, thought I might as well pull the seat and check the air filter, as who knows how long my bike sat on the dealer floor. Bone dry, a wee bit of residual oil on the sealing ring, no grease. Filter was bone dry and a little brittle. Oiled it up and greased the sealing ring. Soo, if you got one of the last new one's in the US, I recommend checking the filter straight away...

OK, air filters, many like K&N, good for the street I suppose, but no good in water, mud and dirt. No good at all. I've always used Twin Air and thought I was doing best, but have read it lets silt through. Twin Air does claim to make one that fits, is size good? I see Moose with good reports and No Toil, no personal experience with either. Lest I forget, my feeling is Uni is like K&N. OK for the street but not much else.
My humble opinion for what it's worth.
Freddy

 

Those IMS Pro pegs are wonderful.

Check out this air filter test. https://haroldbawlzangya.com/air-filter-test/

 

IMO the UNI is nothing like the K&N. The K&N is single stage paper/fiber and the Uni is 2 stage foam. I have no doubt that a properly oiled Uni is providing good filtration, just from the way its designed. If you are going to be going in so much dust that the Uni is a concern, you should just stay stock.

 

Filter socks are good if you ride a lot of dusty trails.
Bike starts running like crap, pull the sock, and carry on.
Multiple filters at home are handy for the shortest bike down time.
I've been using a No-Toil. Works fine.

 

Dealer set up. We always had to oil any foam filters in bikes or ATVs. The dealer didn't do the work.

 

Good advice, Thanks! I didn't realize the Uni was a dual stage foam, that is good, and thanks for the shortcut to the filter tests!

 

I've found Moose Racing's foam filters to be the best I've found so far. Where I ride is SUPER dusty 90% of the time. It's like baby powder floating in the air. It's so bad, we'd have to fall back 100 plus yards behind the bike in front of you. You can't see into the dust more than 40' feet at best. I have to change my filter everytime I ride. Sometimes even half way through a day. This is why I have 4 extra filters oiled in Zip-Lock bags ready to go in my trailer with me. And the reason I can chew the air....LOL

K&N paper filters are Only good for street use. I'd NEVER use them off road, anywhere, dusty or not, period.