Searched alot of airbox lid topics but didn't find one that addressed this entirely. A while back dirtwheels did a pipe shootout. The Pro-Circuit pipe was the only one they ran with the air box untouched. Is this pretty much the only pipe this is possible with? I think they mentioned this was based on the pipe manufacturer's recommendations. I need my airbox intact because of alot of river crossings.

 

its possible to run any pipe with the lid on. With the lid on you loose a few peek HP though. If you run through water alot, you can leave your lid on. If the Pro-Circut was only 1-2 hp away from the rest, and the pro circut had its lid on, then its as good as the pipe that was a little more HP but had airbox mods. you will still have to rejet for a slip-on though, even with the airbox lid on