Here is one of the finest carbs I've ever had the pleasure to set up, it's on my MVVS .91. It has a simple wedge shaped butterfly that is tapered on the front and flat on the back creating a venturi, it is a metered carb and is as linear as an Irvine Jetstream and that's saying something. Unfortunately MVVS chose to discontinue it probably due to mfg. cost.