Removing the KLX250S backfire screen!
Here's a picture of the backfire sreen. You can get to it by removing the seat, opening the airbox, and removing the air filter:
If you have the right tools you can remove the screen without having to remove and dismantle the airbox itself.
Regardless if you can remove the screen this way, or not, I do not recommend cutting the screen out while it is still inside the airbox!!!
You will likely need some sort of a universal joint to get the top nut out.
The needle nose vise-grips on the right are clamped on to an 8mm socket. (A small enough 1/4" ratchet, extension, and universal might also work.)
The backfire screen is held on with 4 nuts. The studs are permanently embedded into the plastic airbox. Here I'm using the T-handle to remove one of the nuts. This one is easy and so is the lower one on the same side. The top nut on the other side is the tricky one. This is where the universal joint is a must!!!.
The last nut at the bottom is pretty hard to find. I put the socket on it so you can see where it is in the picture below. The needle nose vise-grips are used to loosen this one. (For anyone who's drilled a 3/8" hole in the airbox for the crankcase breather, the technique is the same: Clamp-Rotate-Release-Repeat).
Itís a tight fit but if youíre careful you can work the screen out
Take note here that the screen is not symetrical, and it only goes on one way:
Now, the whole point of this exercise ... getting rid of the screen. Just poke your wire cutters through and start cutting:
The screen itself is molded into the plastic, which is why it needs to be cut out. The edges aren't clean and there are small bits of wire left that can tear the foam air filter, so a bit of filing and sanding is needed to clean it up. Here is the finished product
The other side
Airbox Cover Modifications
Installing a KDX200 airbox cover snorkel will let the KLX250 breathe better.
Just removed the stock snorkel and install the KDX200 snorkel.
No modifications are required.
KDX220 Snorkel†††††† OEM Part #14073-1577
You could also just remove the stock snorkel resulting in less air restriction.
I also found that the bike would run even better by leaving the cover off altogether.