I ran across this and thought some of you might be interested

http://www.off-road....wr450f/2003_10/



www.barnumspro.com

Nice! But what about mud & water? Being opened like that will allow water/sludge to go through if you're in the mud holes and do water crossings a lot - especially if you dump your bike in the water on its left side while the motor is still running (been there, done that - see my avatar for the kind of mud play we do) I'd like to see that on an MX bike though, even more air

Speaking of more air, I still am going up on the main after cutting the screen out, and reshaping the cage for better flow. I am at 182 now, and expect it to hit 186.

I was going to suggest having a bolt on cover for wet rides so you could protect the intake some. But after seeing what just the screen and cage has done for air flow, I dont think the intake would like that much change in air flow without jetting to complement it.

Oh yeh, almost forgot. I also wrapped the header and mid pipe with header wrap. It probably increased the exhaust velocity enough to better scavenge the cylinder during the exhaust stroke, so there's not as much leftover exhaust.

Both bikes are exactly the same, so it's not a fluke.

Pretty slick i doubt water intrusion would be much of an issue as long as you keep moving that portion of the box is generally covered by your leg in a standing attack position anyway. remember if she is on her side she will be suckin water no matter what! in will go under the seat just as easily as through the screen.
Has anybody posted the old style fender trick on here yet? A local AA rider around here runs an oldstyle YZ rear fender on his WR's not only does it have the under the seat vents but it is also narrower at the rear and allows some air from the rear sides to enter you have to run some foam on the sides to keep the big stuff out but these boxes are very restrictive and any little thing helps.

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YZ250F_Rider, you're not afraid of backfire (see this link) happening without the airbox screen?

av, I am indeed afraid of it, but I like the increased power too.

I am looking into a k&n air filter with wire mesh that may serve both purposes and yet have the higher airflow. Now before everyone freaks out, I drive my truck in some incredibly dusty roads going to and from ocala to trail ride, and I have yet to see dust inside the trucks air boot. And that filter sees a whole lot more abuse than the bikes ever will.

So when they get here I will do some tough testing and let you know how it all works out.