WR 450 airbox mod

8 replies to this topic
  • M3talH3ad

Posted May 20, 2004 - 04:37 PM


ok, is there a way to remove this snorkle stuff in the airbox in the back of the battery? i hate carving up a new bike. i removed the insert in the pipe and the throttle limiter was removed ofcourse. the bike has 30 miles on it now and really seems to be opening up. i want more. if there is an easy way to do this without cutting let me know.
new pics here M3talH3ads

  • Indy_WR450

Posted May 20, 2004 - 05:15 PM


Put the throttle limiter back in but cut it down to 23mm. You will damage your carb if the slide goes up to high.
The snorkel will come out you have to pry the sides away from the air box by shoving a small screw driver down each side and then using needle nose to pull the unit out. Dont worry about breaking it. It will come out. :thumbsup:

  • mparrish

Posted May 20, 2004 - 05:46 PM


I was looking at the service bulletin for closed course performance options. According to what I read at the dealer, the air box mod is not required on the 2004. Is there a difference between the airbox on the 03 verses the 04? I have kept mine in for now and was contemplating doing the mod until I read this.

  • M3talH3ad

Posted May 20, 2004 - 06:19 PM


sorry, i shoulda said i put the normal YZ450F throttle limiter in it. thanks for the air box tips. anyone else have a technique for the air box, let me know. thanks :thumbsup:

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  • simon@vic

Posted May 20, 2004 - 06:31 PM


:canada:2004 air box's don't have any kind of lid or snorkel. there are two oval like cut out indents on the side of the air box {intended to be cut out}. i was warned against doing this. but i have had no problem at all. and i have done quite a few deep crossings.

  • mtrablue

Posted May 21, 2004 - 12:23 PM


'04 U.S. wr450's still have an insert in the air box top. if there are two holes that appear to only be about an inch square, it's still in there. if there is one hole with a reinforcing web in the middle, it's been removed. it can be removed by using a screw driver to help it over the metal clip that the battery band hooks to.

  • M3talH3ad

Posted May 21, 2004 - 12:54 PM


here is how i removed my air box snorkle for my 04 WR450. The clip that holds the battery in is the key. unhook the

battery and set it forward. you don't need to disconnect it. jam two screw drivers on each side of the clip that holds

the battery down between the snorkle and the battery caseing to make a gap between the snorkle and clip for removing.

once the screw drivers are in place, just yank side to side on the snorkle with needle nose plyers and it should just

pop out. easy as that. also on the 04 WR there are two pre scored holes to remove on the right side of the air box

under the side plate. I just used a flat head screwdriver and hammered them out around the edges. very easy process. i

didn't take pics as i did the work but here are some of the after to show a bit of what i did.

  • blireef

Posted May 21, 2004 - 05:31 PM


Don't you have to rejet a little with all that air coming in?? Indy, did you cut out some of your airbox??
Big Jim

  • Indy_WR450

Posted May 21, 2004 - 05:51 PM


I have a big hole in my air box that is 5" wide x 2" tall at the back just above the fender but below the t support for the battery. It will require rejetting but it is subtle. The big difference is the bike just pulls harder at high revs and revs quicker. A must mod for any WR450. :thumbsup:


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