AirBox Mod Question

airbox mod

I don't know what size bike you are talking about here, but on the 125 and 250 KX you can take the sidepanels off and cut the fins off that run into the airbox. The fins are located on the backside of the sidepanels where some people think that the holes there are used for handles. Those fins restrict airflow and I could tell a big difference when I cut them off of my 2001 KX125. Try doing this first.

berm,
I'm not sure what an 01 KX air box duct is shaped like, but I can promise you that you don't need to put more air in your box; your carb is getting plenty. Scooping or creating a "ram air" does one thing for your bike; it lets in dirt and grit and makes your air filter oil work for its money. At the track, I see ALL the YZ's with duct tape over the eyebrow. There is more than enough air getting to the filter even with these inlets closed off. Under the box on YZ's there is a rectangle hole for moisture and large pieces of crud to egress via gravity, that hole along with the four vents behind the seat let in more than enough air. I'm confident your KX has a similar set-up.:D

Good luck,
Dave

Another mod you could try is to cut out large parts on the flat sides of your airbox and rivet pieces of cloth covered with wire mesh. This helps increase air flow with little dirt. This helped my bike but its not too good for wet or muddy conditions. Good luck!!

the snorkel is on trail bikes, you don't have one on your kx

More Air

Bermshredder, Just cut the fins off the backside of your sideplates. You will feel a pretty big difference. If you resorted to cutting holes in your actual airbox I would get the moose foam inserts. They are about the size of a quarter and they have a rubber grommet around them so you can oush them into the holes you drilled and they will stay securely. It is true that you will have to keep an eye on your airfilter, but it should be cleaned after every ride anyway. I don't know about putting ducttape over the airbox holes like someone said they did on their yz in muddy conditions. I used to put ducttape over the openings to the airbox on my bike when I washed it before I got my airbox cover. When I got to the track I forgot to rip the tape off and couldn't clear anything like I normally did and the bike felt weak. I came back to the truck and told my buddy this thing is running like crap. He didn't say anything and pointed to the tape. I felt stupid. In muddy conditions you can get some foam like what you have in the mouthpiece of your helmet and like what you stuff between the skidplate and the motor and put it into the openings to the airbox. I think dust however is worse on your filter than mud, but thats nothing a properly oiled filter can't stop. More air equalls more ponies. If not why would the pros have holes drilled all in their sideplates and cut the openings out completely on their YZ's. You can :D

What is this "eyebrow that you speak of? on the yz????

I’m sorry, I wasn’t really “speaking” of just the eyebrow. This eyebrow, the tiny air inlet in the top front of the side panel! The one with a total air flow area less than .75 in. sq. The same one you have on your 250 side panel.:p
You would be suprised at the amount of air infiltration into the box just between the seat sides and the side panels.:eek:

Because I don't draw worth a $#!T, I'll give you a pic

Can't see the pic, but I think I know what your talking about. Do you cover the side vent also (the one that has a scoop on the back side of the side panel)?
Jus wonder'n