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i was cleaning out the air filter on my rmz 250 and noticed the screen in the air box and was wondering if you could take it off. Oh yeah, I saw a replacement part on ebay that you can put in to replace the screen. I think its called a backfire screen. Twin air has this kit for a yz250f that has a similar type piece with a backfire resistant air filter.

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Yeah Bro, it's one of the simplest ways to help performance. It's a good idea to re-seal your airbox anyway, WMR has a ring that you put in to replace the screen, you don't want that restriction if you don't need it. You can get a fire proof filter from Twin Air, and then your ready to breath easier.

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there are lots of posts regarding the backscreen removal. just do a search in this forum and you'll get lots of info. bottom line is that removing the backscreen is a quick mod that most people in the this forum will recommend. just be sure to get a fire retardant air filter, or use an non-petroleum based oil like no-toil to clean/oil your filter. you don't necessarily need the twin air kit. there are some forum members that just cut it out themselves.

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The screen is 3 layers thick which must restrict airflow big time.

I cut mine out a month or so ago at the recommendation of the local Kawi dealer

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If your bike backfires I wouldn't recommend removing the screen unless you get a flame retardent filter. For the slight gain in power, it's not worth the risk of burning your bike up 😢

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Check out the silencer packing, if it's gone it will cause popping and backfiring. But I think it's mainly jetting, I run a 175 main 42 pilot 45 wheep and obelr needle in the 4th position. My bike never pops and runs perfect.

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The power gain is minimal by removing the backfire screen. I've tried with the screen and without the screen. If you do decide to remove the screen, definitely get a flame resistant air filter.

The screen helps arrest any backfire flames going into the air filter. I believe it also reduces the chance a bacfire can pop (blow) the air filter off it's seat. If the airfilter gets damaged by a backfire and you don't notice it right away, it could leave a hole in the filter or an air gap around the edge. This would cause dirt to be sucked into the engine, leading to increased wear, decreased performance, poor gas mileage, and generally unwanted bad stuff when it comes to this pretty good motor. 😢

Risk vs Gain? My thoughts are leave the screen in, it doesn't make much difference and the risk is significant. Just my two cents.

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You increase the air flow, as far as how much power is gained; opinions vary. I honestly think that the screen is there for a reason and if it wasn't needed the factory would have removed it in the 05 models.

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I posted before, but I have a pro circuit backscreen eliminator, and I run no toil oil in my filter, which is non-petroleum based--so not likely to ignite. I think the '05 models still have the screen merely from a convenience and liability standpoint. I can't see a manufacturer actually going to twin air and OEM spec fire-retardant filters. its just too much work. I'm on pro circuit's bandwagon when it comes to RMZ/KXF performance. I think there stuff works, and I'll continue to use it. I'll tell you what... I have an old filter I'm no longer using. I'll soak it in no toil oil, and try to light it. if it lights, then the backscreen is heading back in!!

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More on the NO Toil oil and regular filters. I contacted No Toil and asked for their opinion, They do not recomend going without the backfire screen. I ran a test with some old filters and a propane torch. A dry filter (no oil) will burn quite easily, a filter treated with No Toil is really quite difficult to burn, it took about 10 seconds of direct flame to get the element to ignite, it melts first.

From what I saw I think that the chance of a filter treated with No Toil catching on fire is very slim.

We ran the last !/2 of the year with no backfire screen and the bike seems crisper with a little more on the top end. Our bike does not backfire, and I have not noticed any melted filters.

One more thing, my '03 YZ450 has a backfire screen in the filter cage not in the intake boot like the KXF and it only has ONE layer of screen instead of 3 like the KXF. I pulled the screen for 2 reasons, 1 was to reduce the restriction on the intake and the 2nd which is just as important is that I kept getting the filter lip seeling grease on the screen when I put the filter in. The sreen itself may not be that big a restriction but a greasy screen definately is.

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What do you guys use for lip seeling grease.. I like bought some all purpose grease at the auto parts store, but its black and just didn't know if thats what I'm supposed to use...

thanks

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If you change your filter every other ride, you probably don't even need the thicker grease around the seal...you've got to keep the airbox spotless though. but if you need to use something, any sort of waterproof, thick bearing grease (auto, bike, motorcycle) will work fine.

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