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Hola, just picked up a CRF - fired up about it.  Opened up the airbox and found Exhibit A (below).... disassembled and cleaned everything up.  

This phatty screen looks restrictive as hell, even after being cleaned.  Going to soak it a bit more and air blow it out.  But have a hunch cutting that

screen out may open things up a bit.  I will never let the box get that dirty - so I'm not that concerned about dirt getting past the filter, but what's your reaction from people who own it.  I'm not doing anything as of yet, but really interested in who has cut it out and what jet did you toss in to compensate?  Thanks - I'll post some "after" pics. 

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Wow, what a mess.....
If your bike is stock, or even uncorked and properly jetted for your average altitude and outside air temperature that you ride in, cutting out the three layers of screens and completely removing them will make absolutely NO POWER INCREASE or CHANGE the OPTIMAL JETTING in any way.

But if it makes you feel better, buy all means, do it.

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2 hours ago, sunnyrollins said:

Hola, just picked up a CRF - fired up about it.  Opened up the airbox and found Exhibit A (below).... disassembled and cleaned everything up.  

This phatty screen looks restrictive as hell, even after being cleaned.  Going to soak it a bit more and air blow it out.  But have a hunch cutting that

screen out may open things up a bit.  I will never let the box get that dirty - so I'm not that concerned about dirt getting past the filter, but what's your reaction from people who own it.  I'm not doing anything as of yet, but really interested in who has cut it out and what jet did you toss in to compensate?  Thanks - I'll post some "after" pics. 

IMG_2290.JPG

IMG_2292.JPG

AYEEEE CARAMBA!!!!  That looks like the venerable MUD-GREASE the vintage Japanese shop manuals warned us about!

Looks lots more muy Bueno now.

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I started cleaning just the airbox and the carb it took me 7 hours.  I have KTMs, Yamaha WR's... never have seen this screen before.  Almost tempted to screw in a K&N and drill holes for intake for the filter.  With an old Kawi KX450 removing the screen is one of the first steps to get more air in... Jetting is 125, 45, 5/8ths turn.  

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So, in doing some research online, there are nothing but differing opinions on removing it with no info.  One guy found a dyno with no results in removing it.  I have just never seen such a thick pain in the ass of an obstruction on any bike.  (This is my first Honda 230 though).  Going to test it out.  Make sure my air filter is flame resistant, going to run with it and without it and do some dirtbike science. :)

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I removed the screens with a torch by heating/ burning the epoxy.  

It probably makes NO difference in power or throttle response.

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Wouldnt that be a backfire screen ?

So if you remove it you need to run the right filter.

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45 minutes ago, sunnyrollins said:

Right.  It is, but 4 layers of screening and it can get clogged quickly.  J

How does it get clogged with a proper filter?  You should not be seeing dirt on the screens.

 Also, don't run a K&N air filter off-road.  

UNI or TwinAir work great.

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May I suggest doing a "Leakdown" test to verify the condition of the engine since it "appears" that it was ran without an air filter installed at one time?

 

There is much more power available with less than 3% leakage past worn rings then there is by removing the screens on a stock 230f

 

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Frank Nye removes them and Mike Coe leaves them.  With such a tiny engine moving so little air there is likely no way any power could be found on a dyno by removing the screens.  If we were talking about a hi-revving 450 or big 600/650 this could be helpful at very high engine speeds but would do little for most average engine operating speeds.

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Lol, if I got paid as much as Frank to remove the screens from a 230f air filter box, I would do exactly that on every one handed to me.....

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I'm going to run this bike into the winter, then just pull the top and maybe the bottom end out and redo everything.  Who knows how much dirt was brought in there.  The funniest part of this bike is the PO crammed so many things on the bars then cut off the throttle and grip leaving 3" to fit your hand in the grip.  Bought all new stuff for the bars....

 

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I removed the screens because I have never seen 4 layers thick screens on any bike. Being that I heavily grease my Uni sealing lip. It was getting on the screens restricting air flow. I use white grease so I can see If seal lip leaking. So now the grease goes in motor.Has not hurt the last two years.  

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On 7/22/2017 at 10:00 AM, bajatrailrider said:

I removed the screens because I have never seen 4 layers thick screens on any bike. Being that I heavily grease my Uni sealing lip. It was getting on the screens restricting air flow. I use white grease so I can see If seal lip leaking. So now the grease goes in motor.Has not hurt the last two years.  

Four layers of screens. I don't even use window screens on my house. 

The Wolf had a extra filter over the air filter beather hole on his girlfriends CRF230. When I removed it the bike started running right. 

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I'm wondering if the No-Toil grease I used last time will do this sorta thing.  It is the weirdest stuff, all watery and separated, took me longer to knead it back into proper grease form than it did to service the filter.

What kinda grease do all y'uns like to use? 

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The net gain of air flow has to exceed the possible gain of flow through the engine. I removed it on one 230. I don't think I gained anything. 

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23 minutes ago, MetricMuscle said:

I'm wondering if the No-Toil grease I used last time will do this sorta thing.  It is the weirdest stuff, all watery and separated, took me longer to knead it back into proper grease form than it did to service the filter.

What kinda grease do all y'uns like to use? 

I gave up on no toil. I use bel Rey filter oil and white lithium grease. 

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