Has anyone ever tried the air box vents? They are small 3" vents that you put on your air box. Do they actually help? Or would they require you to rejet?

 

these will let much more air in your quad and you must rejet unless for some reason you are running rich right now

 

It says they are adjustable, to allow as much as a fraction, to alot of air flow.

 

I use the square ones in the Rancher, to adjust for altitude changes. I have two of them in the airbox lid. They work great!

My typical mountain ride starts in the valley at ~4,000', and ends up in the mountains at over ~10,000'. As I ascend, I open the valves a little at a time, until I am at max altitude and they are wide open. And if I am really up high, I just pull the lid off completely. I of course, have to close the valves as I descend in altitude, or I would end up lean and damage my engine!