Backfire screen removal?

MotoX85
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MotoX85 3/1/2014 9:12am
3/1/2014 9:12am
MotoX85 wrote:
I can't really read this, can't find were stock is, but no worries, it looks like a 1 hp increase according to this chart. Definately worth...
I can't really read this, can't find were stock is, but no worries, it looks like a 1 hp increase according to this chart.

Definately worth burning your bike to the ground.

IF a certain person is reading, I guess all you need is a 12 pack of beer handy so you can put out the fire. How'd that work out for your $8000 2013 450 that is a pile of melted plastic now.
moto38 wrote:
There is literally dyno-d proof that it helps to remove the screen, and you are still saying its not worth it because it could burn the...
There is literally dyno-d proof that it helps to remove the screen, and you are still saying its not worth it because it could burn the bike "to the ground". If OP buys a flame-retardant filter, then your argument is that it could get sucked into the engine, in which case it would take a filter in pretty bad shape for that to happen.

The force that a 4stroke intake pulls with would have to be greater than the force required to suck an ENTIRE filter, cage and all, through the intake. That wont happen. Plz remove tin foil helmet
Yes it will and can happen, 30 year mechanic here, step of away from the keyboard. I've had it done on my bike (with screen in it), I have seen no less then 3 bikes burnt, 1 totally to the ground and 2 just the airbox and seat.

It is not worth the 1 hp gain to risk burning your bike to the ground for the average joe. This people get on here thinking they should do things that others with unlimited resources are doing and then bitch about why their bike doesn't last. There are a hundred different ways to gain 1 hp, without removing a safety device that is there to ensure joe retard redneck doesn't start a $8000 campfire. I doubt very seriously that you have exhausted every other modification option and are left with the only hop up left is screen removal.

Other threads are bitching cause 450s (your dyno chart) are too powerful for the average joe and now we want to remove safety devices to gain 1 hp. Save your money and by an exhaust, cams, flow the head, different mapping, anything before removing safety devices to gain an amount of HP 99.999999% of riders could never feel.
jhansen510
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jhansen510 3/1/2014 9:46am
3/1/2014 9:46am
You sure like to argue dont you MOTOX85? Your initial post said that removing the backfire screen does not equal more power/better response. YOU ARE WRONG THERE. If doing this mod you should be smart enough to use a filter that is flame retardant. If you are not that smart then you deserve to have your bike burnt down. I dont think you would find one bike at an ama pro race that has a backfire screen in it. Its the combination of all the little things that makes a strong running 250f. What the hell do you care what I and others do to our bikes? After all we will need mechanics with 30 years experience to fix our mistakes.... Good god man.
MotoX85
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MotoX85 3/1/2014 10:02am
3/1/2014 10:02am
jhansen510 wrote:
You sure like to argue dont you MOTOX85? Your initial post said that removing the backfire screen does not equal more power/better response. YOU ARE WRONG...
You sure like to argue dont you MOTOX85? Your initial post said that removing the backfire screen does not equal more power/better response. YOU ARE WRONG THERE. If doing this mod you should be smart enough to use a filter that is flame retardant. If you are not that smart then you deserve to have your bike burnt down. I dont think you would find one bike at an ama pro race that has a backfire screen in it. Its the combination of all the little things that makes a strong running 250f. What the hell do you care what I and others do to our bikes? After all we will need mechanics with 30 years experience to fix our mistakes.... Good god man.
Not arguing, just discussing. It was a quick response, thinking that would solve the want to ruin a bike, but since others have posted, more explanation was required, but yes, I still do not think that removing a screen makes much of an improvement in HP, if any.

My problem is I think people actually care about knowing facts.....this is where I am wrong. I post a response thinking that people like knowledge and wisdom when in fact, no matter the answer, they just want to argue because they have anonymity of internet and usually do not have much of a life to talk about (ala Facebook). I simply base my opinions on 30+ years of wrenching, riding and racing and also throw into the mix of being a 27 year Turbine Engine Mechanic for the Army and that usually gets debated by some 14 yr old squid that because he can jump "the quad" on his 250F, he knows more than I do.

Funny thing is, when I am in person with people, I never have any of the issues I have here and am usually the one at the track people ask for mechanical help......go figure.
MBR
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MBR 3/2/2014 10:50am
3/2/2014 10:50am
Zesiger 112 wrote:
While you are at it, I saw an article in mxa, that if u turn the nozzle on the throttle body it will have better throttle...
While you are at it, I saw an article in mxa, that if u turn the nozzle on the throttle body it will have better throttle response, really easy to do. Just look it up.
We tested this one also:
- on dyno it made about 1 hp less, but the torque was a bit better on low rpm.
- only one test rider from three felt it made any difference on track.

You definitely can feel the difference between stock and power flow filter, bike has better throttle response and it's much crisper all around. If you remove the backfire screen, just use filter and oil that is flame repellent, it's that easy.

The Shop

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project racer 3/2/2014 11:25am
3/2/2014 11:25am
Seems to me upon a backfire situation, it would be excess fuel being spit back through the carb / injector , saturating the filter a bit, that would cause the fires. Do the flame proof oils / filters nullify this scenario ?
garrettcibak71 3/2/2014 6:30pm
3/2/2014 6:30pm
RMRider1 wrote:
Why don't 2 strokes have them? I just used a RM screen on my RMZ...$3 swap. Def snappier and my '13 RMZ I can swap out...
Why don't 2 strokes have them? I just used a RM screen on my RMZ...$3 swap. Def snappier and my '13 RMZ I can swap out plugs and make it richer if need be.
did you remap it once you put the RM screen in ?
garrettcibak71 3/2/2014 6:42pm
3/2/2014 6:42pm
Zesiger 112 wrote:
While you are at it, I saw an article in mxa, that if u turn the nozzle on the throttle body it will have better throttle...
While you are at it, I saw an article in mxa, that if u turn the nozzle on the throttle body it will have better throttle response, really easy to do. Just look it up.
MBR wrote:
We tested this one also: - on dyno it made about 1 hp less, but the torque was a bit better on low rpm. - only...
We tested this one also:
- on dyno it made about 1 hp less, but the torque was a bit better on low rpm.
- only one test rider from three felt it made any difference on track.

You definitely can feel the difference between stock and power flow filter, bike has better throttle response and it's much crisper all around. If you remove the backfire screen, just use filter and oil that is flame repellent, it's that easy.
I don't plan on messing with the throttle body at all. I am just going to remove the screen and add a non-flammable no toil filter. did you guys remap the bike during the test? and have you had any problems since it was removed?
jhansen510
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jhansen510 3/2/2014 8:21pm
3/2/2014 8:21pm
Dude your question has been answered 10 times. If you are just removing the backfire screen you are probably ok without remapping. If you have a pipe then remap for sure. If you want to remap even without doing the screen or pipe you will see benefits. A remap can move the power to where and how you want it delivered.
mxb2
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mxb2 3/2/2014 8:27pm
3/2/2014 8:27pm
jhansen510 wrote:
Dude your question has been answered 10 times. If you are just removing the backfire screen you are probably ok without remapping. If you have a...
Dude your question has been answered 10 times. If you are just removing the backfire screen you are probably ok without remapping. If you have a pipe then remap for sure. If you want to remap even without doing the screen or pipe you will see benefits. A remap can move the power to where and how you want it delivered.
x2lol remap your bike man.
MBR
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MBR 3/3/2014 5:29am
3/3/2014 5:29am
garrettcibak71 wrote:
I don't plan on messing with the throttle body at all. I am just going to remove the screen and add a non-flammable no toil filter...
I don't plan on messing with the throttle body at all. I am just going to remove the screen and add a non-flammable no toil filter. did you guys remap the bike during the test? and have you had any problems since it was removed?
We did, but it run ok with stock map also. However I definitely recommend the HRC "response" map for CRF250, it really helps with top end. According the main designer of CRF line, for best results you should go little richer through the whole ecu map. We'll probably go to dyno later this spring to test a few more settings just for fun.

Pit Row

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