One word of warning, It has been recomended by tuners thst you should not run the lid off the air box with the stock carb as it is a CV carb and needs a set amount of vacum before it wil give full throttle.

Now many others dissagree with this I wont go into it in detail but if you search for it you will find a few past threads. i tried runs with it on and off myself and the most i can say was it was inconclusive .

Im not sure how much you will benefit from extra revs on the trails as the rotax makes its power low down, maybe some other guys who ride similar terain would come in with some info on this, Its somthing i would like to hear more on.

 

It is not the fact of running with the lid on or off that matters. If you tune the carb correctly, the bike will run very well without the lid, or the complete air box for that matter. I've got a lot of Dyno time messing with this whole air box/lid thing. Theres no way around it, the air box with the lid on or off is a restriction. I tried it every way possible, even no lid with holes drilled all over the air box, it is still a restriction. It takes alot of time to get the carb right and most people don't put the effort into getting it right, so they say it doesn't work.