Airbox snorkel cut out size

[NsrJohn]

Hi does anyone know the size of the cutout in airbox lid, for the stock snorkel? Thanks.

[kdxdazz]

Surprised no replies for this, would have thought many people with airbox lids, mine has the snorkel in it so can't give you the airbox cutout size

[SS109]

I wish I could answer but the lid was removed from both of my KDX's when I bought them.

[Molly's 70]

OK, here's what I did to my airbox lid. I am unaware of any certain size to cut it out to. For my case, I wanted more air, so I removed
the snorkel. Then I carefully clamped the airbox lid in a vice on my friend's vertical mill. I just milled the elevated part where the snorkel goes
to about a 2 x 4-inch hole. It's really about 2 1/8 x 4 1/2 inches. I just eyeballed it. I used a 2 flute 1/2-inch end mill.

I like a quieter bike, so this worked for me better than with the lid removed. I did not use any science, I just did it.

[KDXGarage]

As mentioned, no exact science. No need for an air box lid in dry non-super dusty weather. Lid on for wet rides. My MX bikes don't have lids.

[kdxdazz]

As mentioned, no exact science. No need for an air box lid in dry non-super dusty weather. Lid on for wet rides. My MX bikes don't have lids.

Definitely a need for an airbox lid and snorkel depending on riding style and conditions, your statement on MX bikes is already an answer, MX bikes are only interested in high RPM and an aggressive power delivery, enduro on the other hand is the opposite, a smooth, linear power delivery at just off idle is desirable , even road bikes use a snorkel,i remember listening to people on the internet when I was a teenager and drill holes in my airbox lid on my rgv250, the amount of low end torque lost was incredible applified by it being a twin cylinder bike with already near zero torque
The airbox lid cut out size creates higher air speed at lower rpm which results in more efficient cylinder filling, contrary to popular belief the snorkel is not there to reduce noise , although it does help with that as it has no sharp edges unlike an open box ,it delivers air that is less turbulent for the cylinder to draw from, hence why the kdx snorkel is a twin plenum design although I admit to not fully understanding the design as my drz is a single plenum design
I have reinstalled all the snorkels on my bikes with very pleasing results especially at the lower RPM range where most of my riding is done
I'm guessing the OP is asking for the airbox cutout size as somebody has previously hacked it up which was the case with mine too and I had to plastic weld it
However this is read it's meant to be tactful and informative

[JimmyB]

Stock hole size is 31mm x 85.5mm

[NsrJohn]

Stock hole size is 31mm x 85.5mm

Thanks for that appreciate it

[Molly's 70]

Here is a picture of my airbox lid. I kept the stock one so I can go back if I want.

DSCF0037.JPG (1.98 MiB) Viewed 1059 times