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CRF-150 Flame Screen removal?

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I am installing a Uni filter and want your thoughts on removing the flame screen.

Is it really needed.....as we never had these on the pre-EPA bikes?

Is this just for noise reduction, and any performance gains by removing it?

The bike has been re-jetted & exhaust mods done.

Thanks.

1f2da502.jpg

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I've bought aftermarket air filters and cages for my CRF450X and WR250F and used them without any issues. NoToil Superflo kits claim flame resistant foam used on filter. I've got the UNI filter on the CRF230F. I've thought about removing the screen, as well. Might have to tweak the jetting a little, if the screen removal actually improves the air flow.:busted:

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My 230 was rejetted, snorkel and baffle removed, with a uni air filter, ran like a beast, thing was a tank, leave the screen there, i doubt youll see better gains by removing it, and if the carb does happen to backfire or something, it will prevent a fire. i say leave it.

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The screen will flow many times the amount of air that even a highly modified 150 could ever use. Your performance gain will be zero. It is called a flame screen because in the case of a backfire through the carb you will not catch your filter on fire. I saw a CRF250R catch fire at an MX race. A track worker got a fire extinguisher there within a few minutes and it had already destroyed his airbox, side panels and seat. So how long for you to get an extinguisher out on the trail. Leave it in. Jeff

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On a local rider forum, one guy posted a backfire started an airbox fire. Luckily he was in his garage with tools at the ready to pull the seat (different bike) and get to the airbox to put out the flames.

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He probably cleaned it with gasoline.:busted:

Again, been running without backfire screens with NoToil filters for a couple of years with no issues.

As long as the screen is not a significant flow restriction, the improvement will not be significant. The mesh looks a little dense to me, and it's hard to not get air filter oil on it, so I don't know.

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He probably cleaned it with gasoline.:busted:

Again, been running without backfire screens with NoToil filters for a couple of years with no issues.

As long as the screen is not a significant flow restriction, the improvement will not be significant. The mesh looks a little dense to me, and it's hard to not get air filter oil on it, so I don't know.

People ride for years on the street without helmets, but their heads still split open when they smack it on the pavement :busted: Just because a bad thing hasn't happened to you personally, it does not mean it wont happen. Leave the screen in. Removing it has ZERO effect on air flow. If we can run modded 230s with it in without starving for air, what is the gain for a stock 150 motor. Jeff

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What does riding on the street without helmets have to do with backfire screens? :busted:

Myself, and thousands of others, have been running aftermarket, flame retardant air filters without backfire screens with no issues.

As I said, if the effect on airflow is not significant, then the performance change will be insignificant.

Your point is valid that the same airbox is used on 150's and 230's, so if there isn't much of an effect for 230's then there wouldn't be much of an effect for 150's.

However, part of the fun of owning dirt bikes and cars is modifying them to see if you can increase performance, even a little bit.:busted:

Here's a pic of the NoToil filter w/o backfire screen and a pic of a stock 2006 WR250F screen.

DSCN0048.jpg

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Now if you showed me a pic of a CRF150/230 flame retardent filter it might make a little sense. Now when Billy Bob thinks well shucks Sofie Dog aint never had no trouble. I'll just rip that ole screen out and go way faster. Then his carb pops and sprays gas and fire onto his stock filter (yes the carb supplies the fuel, NOT washing the filter in it) and his bike burns can he send you the bill? Unless he can your advice should be, Leave the Screen In :busted: Jeff

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cut mine out at the track with a box cutter 2 years ago lol

gains = none

but the screen is like a 3 or 4 layer sandwhich of different metals and such. pretty neat

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Did a quick search. Couldn't find flame resistant foam filter specifically made for CRF150/230F. In order to safely remove the screen, you would have to adapt a filter from a different bike (or, according to some folks, carry a fire extinguisher). Hardly worth the effort.:busted:

Also, if removing the screen made a significant difference in airflow, you would not see an improvement by simply cutting it out. You would have to rejet it to take advantage of the change. The change would be minor and difficult to detect by just riding it and not putting it on a dyno.

Edited by Sofiedog

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I've never been around a bike with the screen left in. It is put in by lawyers, not engineers. As others have said, the performance gain is 0 on these lower hp bikes. On a 450, about 1 hp.

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I've never been around a bike with the screen left in. It is put in by lawyers, not engineers. As others have said, the performance gain is 0 on these lower hp bikes. On a 450, about 1 hp.

Lawyers point out problems, Engineers find solutions to them. The backfire screen is an engineering solution to a very real problem. Jeff

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