That approach won't work here. Too much fine dust, especially in the deserts. The only hope of keeping it out is to have the filters thoroughly oiled all the way through with an aggressive filter oil. To see it you would swear you couldn't grind rocks into that fine a powder. The stuff hangs in the air like smoke, and weighs next to nothing. Not so bad on a well groomed track of course, but....
Yea the dust out here can get pretty yucky. Even after a shower the dirt/dust is still blowing out of my nose Too bad I wasn't a faster rider then I could be the leader or closer up front on some of these rides. Cover the air boot up and rinse out the airbox with simple green and let it dry!