Thumper Air Box Mod

[VET393]

Where is the thread on CRF450 airbox mod. I need to see the pics of what to trim away?:

[FFRacing11x]

Look no further

[Imahoot393]

Just a stupid ? for my info....why do you want to do the airbox mod?

[FFRacing11x]

less restrictive...accomplishes the same as drilling ugly holes in the side of the airbox. It does make a difference.

[Woody_393]

Hey FFR, would you remove the backfire screen as well? Would that also help? I think it would, but not sure if it's worth the risk. I kind of think I've got more power then I can use as it is.

And won't you see the increase in the upper RPM's vs the lower?

[cowboyona426]

Lookin' fer threads in all the wrong places...

[FFRacing11x]

I would definately remove the screen...it is nothing more than a liability issue.
The airbox mod shows up as an improvement across the board.

[FFRacing11x]

Cowboy, this mod is an even bigger improvement on the YZF...the lip extends at least an inch more than on the CRF.

[Woody_393]

Cool, thank you FFR, I think I'll go do it today.

[cowboyona426]

Got pics of the YZF version FFR?

[FFRacing11x]

It's the same except it's black and blue instead of black and red:

[cowboyona426]

Wise guy :
So basically, you just cut off the upper back portion of the airbox??? I don't remember mine having a big lip back there, but it easily could. I'll look into it. I'm also thinking about buying a Twin Air flame retardant filter and modifying my cage or picking up a YZ 250 cage and giving that a shot.

[FFRacing11x]

The airbox is cut where it and the fender come together. An exacto knife works best.

[VET393]

I have already removed my screen this is next.

[strykmaster]

I just took out my backfire screen and the side panel vents. (very easy) The airbox mod is next. The plastic looks a bit thick for an exacto knife. Is there a better (cleaner) way to cut it?

[VET393]

I thought about warming mine up alittle before I cut it.I will let you know how that works.

[ThumperTDC]

I did something similar to my XR airbox. I used my dremel tool, and it worked like slicing a hot knife through butter.

Before

After

[VET393]

nice :up:

[strykmaster]

I'm using a Stanley utility knife with a fresh blade and it's working awesome

[Woody_393]

The key is to get a good line and then just keep cutting (going deeper everytime) until it's removed.


strykmaster, what's the reason for removing the vents (the part sticking into the airbox)?