Anyone use a K&N on a 426?

Thinking about switching from my foam Uni 2 stage filter to a K&N on my YZ426. Anybody out there running the K&N and how do you like it?

I have been running one on my 2000 426. It lets the air flow better but when I did a rebuild 2 months back the carb had dust inside of it and the intake was dirty also. So if you are in dusty conditions I recomend putting an outer wear over the filter. But after I saw the dirt in the carb I went back to a Twin Air filter.

Don't. K&N's are actually a better filter, and have better airflow than foam, but they have two significant shortcomings.

A layer of fine dust clogs them more quickly than it does foam, and the engine will pull dust through the filter sooner. A well oiled foam filter can hold two or three times its weight in dirt, gauze filters can't. I know you clean your filter every ride, but what about that really dusty day?

K&N's filter well only when they are correctly oiled. This same thing is also true of foam, but K&N's are much more difficult to oil thoroughly, so an awful lot of K&N's are running around working at half their capacity, letting dust into the engine. You just can't squeeze the filter and work oil through it as you can foam. Specialized spray oils like Maxima FAB-1, and aerosol version of FFT, make it somewhat easier, but they're expensive compared to bulk liquid oils, and either way, it's a mess.

I cleaned mine after every ride but I guess that I just didn't oil it correctly. I live in Arizona and most of the time when I ride it is dusty. Is it better to put a Pre-filter on it?

Is it better to put a Pre-filter on it?
It's better to use a good, properly prepped and maintained foam filter.

We will not use k+n filters,they pass fine slit.Had the slide stick wide open.We have 20 dirt bikes in Baja.Uni filters have been the best for us.

Keep Up On Maintenance And Use A Pre-filter. My Carb Is Good And I Love The Power Gain

We have used pre filters with the k&n filter,but it cut down the power.No k&n's for us in Baja

Not for desert racing in SoCal, either. After a 2-3 hour race, my Twin Air looks like an iced bundt cake. No dust inside, though, and no noticeable drop in power. :thumbsup:

Hey Gray,

What type of oil do you use on your twin air. I just bought one and the oil doesn't seem as tacky. How much do you use?

I use Maxima FFT. When I open the bottle, I don't tear out the foil seal, I put a hole in it instead. I turn the filter inside out, shake a good amount of oil on the interior, and work it in. Then roll it right side out, oil the flange and the exterior, and work that in. I add more until it gets to the point that I can really squeeze any part of the filter hard and excess oil will rise from the foam. That means it's saturated. Then hang them out for several hours so any excess that drips off won't do so in your air box.

I used the twin air oil and it doesn't seem tacky enough. I saturated it completely and it is a dark blue in color and all the excess has dripped off but the filter isn't as tacky as i would like it to be. I guess I will switch to another brand and see how it works. Thanks again for the info.

I have now been running a Twin Air filter with Maxima FFT and couldn't be happier. Not a spec in the boot.

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