I'm not sure if it's a technical term, but I hope you know what I'm talking about. One you hit the top of the revs, the engine emits that trademark 2-stroke "burbly" sound. Almost like a rev limiter kicking in.
What goes on in the engine at that point? Fuel starvation? Vapor lock?
What can be done to bring the revs higher before burbling? I hit it sooner than I like, at least in first and second gear. Especially before the engine has warmed up. In third and fourth my (essentially stock) engine doesn't quite get there.