09 yz450 airbox question.


17 replies to this topic
  • ash102

Posted January 20, 2011 - 11:10 AM

#1

I was told by a friend that the screen in the air filter cage needs to be removed. Do you guys notice a difference?

  • mdkcrf250r

Posted January 20, 2011 - 12:08 PM

#2

a fraction of a horsepower you would never ever notice and you risk catching the bike on fire. You tell me if its worth it.

  • grayracer513

Posted January 20, 2011 - 01:38 PM

#3

No one I am aware of has ever documented any gain from removing the screen. Doug Henry's crew spent a lot of time on the air box setup of his '03 (?) bike and concluded it was a waste of time to bother with it at all.

  • FZ1426

Posted January 20, 2011 - 04:12 PM

#4

It doesn't "need" to be removed, and there may be no measurable gain in horsepower, but removing it provides for crisper off idle throttle response.

It is noticeable on initial power application (out of corners for example) if you are a moto purist. :smirk:

A YZ250 filter cage is a direct replacement without the screen.

  • grayracer513

Posted January 20, 2011 - 04:42 PM

#5

It is noticeable on initial power application (out of corners for example) if you are a moto purist.

I'm a "moto purist", and my experience is that there is nothing to it. But if anyone wants to spend $25 to find out, go ahead.

I would not advise simply cutting the screen out of your existing cage. Doing so runs the slight risk of having loose bits of stainless wire fall free into the intake.

  • dalonar

Posted January 20, 2011 - 05:59 PM

#6

its a joke, there can only be so much pulled through the intake and the screen will let far more air through than the filter will.

  • Jim813

Posted January 20, 2011 - 07:00 PM

#7

I would not advise simply cutting the screen out of your existing cage. Doing so runs the slight risk of having loose bits of stainless wire fall free into the intake.


Not to mention being poked everytime you wrap your finger around the cage where the screen once was.

  • FiremanKay

Posted January 20, 2011 - 07:48 PM

#8

as funny as it may sound but in my line of work screens always go. dont quote be but I believe screens create a 30% loss of are movement. Whenever we are venting a home, the screen always goes and it make a big difference. Stick a fan in your window at home with a screen in and then without, substantial difference. Anyhow, I dont know at all if this translates at all to the airfilter. I dont want to say one way or another, I just know an actual place it does.

  • grayracer513

Posted January 20, 2011 - 07:54 PM

#9

The analogy doesn't work because the windows of which you speak don't have a dome of oiled foam over them. If the air filter were not there, then removing the screen could potentially increase air flow at full throttle. But the fact is that the filter is more restrictive than the screen, so removing the screen does nothing.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • FiremanKay

Posted January 20, 2011 - 09:26 PM

#10

The analogy doesn't work because the windows of which you speak don't have a dome of oiled foam over them. If the air filter were not there, then removing the screen could potentially increase air flow at full throttle. But the fact is that the filter is more restrictive than the screen, so removing the screen does nothing.


Perfect logic gray, I'm with you on that. I didnt think of it that way.

  • FZ1426

Posted January 21, 2011 - 02:49 PM

#11

It's not really about flow rate per se. It's about accelleration of the intial charge of air from the airbox.

It's about getting a slightly cleaner and more voluminous pocket or slug of air just at initial throttle opening. That's all.

Obviously most people can't feel it or don't give a shit. I'm not one of them.

The intake boot shape on modern four strokes is as highly engineered as the exhaust pipe shape. Small changes in shape and volume make a big difference in the feel of the motor. Not necessarily horsepower but "feel".

With the screen removed the initial charge (between the screen and the filter)doesn't have to accellerate through the screen, the effect is a slightly denser air charge and quicker response.

No big deal. It's not going to lose you a race, and a race team should probably leave the screen in for liability purposes. It wouldn't look too good for their sponsors if their bike burned up...

I've never had a problem with my bike burning up...Yet. I guess if it does then it's obviously time for a new bike.:smirk:

  • grayracer513

Posted January 21, 2011 - 03:16 PM

#12

With the screen removed the initial charge (between the screen and the filter)doesn't have to accellerate through the screen, the effect is a slightly denser air charge and quicker response.

That's a good theory, except that the relatively still air between the filter and carb can't be accelerated with or without the screen until air flows through the filter to replace it.

Magic Feather.

  • FZ1426

Posted January 21, 2011 - 03:22 PM

#13

That's a good theory, except that the relatively still air between the filter and carb can't be accelerated with or without the screen until air flows through the filter to replace it.

Magic Feather.


Sure it could. But then you'd have a vacuum. Thus a dead motor that even a magic feather couldn't fix. And lousy throttle response.

  • grayracer513

Posted January 21, 2011 - 03:29 PM

#14

So removing the screen fundamentally changes nothing.

  • FZ1426

Posted January 21, 2011 - 03:48 PM

#15

So removing the screen fundamentally changes nothing.


No. It changes something.

  • dalonar

Posted January 21, 2011 - 06:19 PM

#16

ok ok ok, i found this sticker once that i put on my bike and it made me go so much faster!

  • ectm3

Posted January 21, 2011 - 06:54 PM

#17

If you do want to eliminate the screen,id go with a loud mouth air filter kit;or a pro design kit.They come with a billet housing that attaches to the air box.So all that is required when changing/replacing the filter is a 8mm socket.I run the pro design kit on my yz450f and my yfz450 its the cats a$$.

  • ash102

Posted January 21, 2011 - 11:34 PM

#18

Thanks for the replies. I did not think it would affect it much if any. The power the bike makes it great for the woods. Now if I could keep it from stalling in the tight stuff it would be perfect.





Related Content

Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Forums
Photo

YZ450F 03 Sparks driving me crazy by SirAttard


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Forums
Photo

First Hare scramble tips by dhend8


Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies
Forums
Photo

Is it worth it? (Cam and High compression piston) by macgi77


Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.