backfire screen

I know several people who just remove the screen and run a normal air filter.Claim they have never had any problem with this in crf 450.

please comment

I thought the same when I felt how big it was. Years back I saw an air filter burned on the inside on an older xr. I guess if all is running right and not back firing it should be alright. I still run mine though.

I ran my 2006 all last year w/out the screen.

No problems,

Just adjust the fuel screw and ride.


I've owned and have ridden with a bunch of CRF's, and no one I know has ever left the screen in. I hear rumors of the occasional fire on the internet, but not in my circle.

so, you are suggesting to remove the screen from the plate? i would think that plastic cage on the crf's isn't very stable without the screen.

how do you cut it out? wire snips?

There are a few tabs that hold the screen in. They can be bent to remove the screen. I had my screen removed for a while but have since put it back on. From what I hear there are no real performance gains with the screen out. Better safe than regret when /if the filter catches fire.

From what I know, the screen is a sort of diffuser per say. It shouldn't let a flame through. There are diffusers on the street bikes as well.

Next time you're cleaning your filter, after washing it thoroughly, hold a lighter under the screen, and the flame should stop and not go through. Obviously the heat will pass, but the flame shouldn't go through.

There are no hp gains by removing the steel cage inside the air filter on the crf 450r. I have run them both ways and cannot feel a difference. I have seen melted foam on the inside of the filter. This may not cause a fire, but may compromise the filter from doing it's job, keeping the dirt out.

The crf 250 does get hp gains from this mod, but you must re-jet to fatter jets.

to get the feel from the 450 you will have to re-jet, with more air you need more fuel. you could always buy the twin air powerflow filter (not the kit just the filter) and throw it in you air box, its got a laminated layer inside so it doesnt melt or catch fir. thats what i did and i have no worrys.

yeah, if you are doing this i highley suggest a twinair laminated air filter

I'd leave the screen in - and it has nothing to do with backfires.

Iv never had a screen in any or my 450's. They all have been jetted correctly, so I have been able to tell a performance gain. Now I cant sit here and say that all that performance came from removing the screen only, b/c they have been jetted before I even ride them. I like my twin air set up b/c I have about 14 filters laying around, so I can always have a clean, fresh filter ready to go when I wanna go practice, or leave for a race.

I'd leave the screen in - and it has nothing to do with backfires.

your saying the backfire screen is not for you know something knowone elese here does?

I would guess you'd get maybe 1 extra hp by removing the screen. Can anybody here say that they are so fast and manly that they have to have that miniscule gain to win local races? Come on.

I would guess you'd get maybe 1 extra hp by removing the screen. Can anybody here say that they are so fast and manly that they have to have that miniscule gain to win local races? Come on.

not without a re-jet you wount

I would guess you'd get maybe 1 extra hp by removing the screen. Can anybody here say that they are so fast and manly that they have to have that miniscule gain to win local races? Come on.

Who said anything about local races? I travel around the entire east coast racing.

Oh, sorry Ricky, I guess you DO need the extra tiny HP increase! :thumbsup: :thumbsup: :confused::ride: :ride: :D :D

Years ago, someone dyno'd a CRF450 with and without the backfire screen. I think it was FFR who did it. There was absolutely no difference. No gain in performance what so ever.

Although he did say that there was a 1HP gain if you removed the right side number plate.

So if you want a 1HP gain, leave the backfire screen on there and take off the number plate. You'll look way cooler too.

for some reason 1hp still seems like a lot to me for basicly no money spent and 15 minuts of your time

Kind of pointless when most people don't even come close to using the stock 53hp. Not worth the tiny risk of fire to me.

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