Has anyone used the lowboy tpi vents or similsr adjustable airflow vents? They are approx 3" x 3" and fully adjustable for very little to alot of extra airflow. I want to know if they helped increase power, and if its a must to rejet? I have a 2006 650V2, and am looking for a little more power.

 

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!