Uni foam air box vents---what size hole?

[ccdhowell]

Gonna let a little more fresh air into the airbox of my Big Red since I have done a little motor work to it. I ordered a set of these from Rocky Mountain and wanted to drill the holes today, they haven't arrived yet.

What size holes do you drill/cut? Seal them with silicone too?

Thanks,
Chris

[Bryan Raffa]

one inch hole saw with pilot bit..some silicone to insure they hold

[Dirtcrasher]

Are you jetted for the lid being off? I cut 6 of these into the 350X airbox lid it it wasn't enough, not even close. It ran like dogchit on topend. Popped off the lid and it was back to normal. Maybe 12 would have done it but they don't seem to let in much air.

It's kind of a crummy situation. You get your main jet as fat as you can for an open lid and then you can't run a lid in muddy/wet conditions unless you swap some jets around.

I used a 1" forstner bit and they have a pop out that holds them in pretty well, silicone won't hurt though....

[ccdhowell]

Thanks guys, I'm gonna go buy me a 1" hole saw. Yeah I wanted these cause I don't want to loose the lid. Thought they'd let in more air. Raffa, nice pic, just may end up putting more than 6 in my box too, if it's big enough.

DC, I'm in the final stages of a rebuild on my big red. Haven't jetted anything yet, but I understand I will have to change jetting some. I want to put these in and jet for these with lid on the airbox.

[Dirtcrasher]

I'll bet if you jet it with these in place that you'll find a happy medium but if you've got some motor and exhaust mods, I'd run at least 12 of them.

Honestly, I was shocked that the 350X with 6 of these was starving for air so bad....

Hmmm, Raffas got a nice setup there!!

[the tecate kid]

My god Raffa! Milk anyone?

[neo19672000]

DC I feel your pain I had 8 in mine and it wasn't doin the trick so I went bigger :D

59163

[ccdhowell]

neo, I like that. I was browsing around the uni website and found that uni makes flat pieces of foam so you can make your own filters. No doubt they had something like that in mind. I'll probably end up putting something like that in my lid too. Problem is that unlike my Tecate airbox lid on the side, this lid is on top. Seat comes within 1/4 inch or so, don't know how much air it would flow with the seat so close. It may be better to just replace a side of the box with a foam panel.

[Bryan Raffa]

I was thinking of doing something like neo on the 200x but taking a old outer ware and stretching it over the hole and holding it down with some thin alum strips and some small screws.. k&n also has power lids you might find something the right size that will work similar.