Higher compression tends to need more Octane. Before messing with the jetting anymore, get some race gas (105+ preferably leaded) and mix it at least 50/50 with premium unleaded. Try it out and see if your midrange ping goes away (probably will).
What premix do you use and at what ratio?
All motors are different and tend to need individual set-ups to run good (think of a guitar-10 may be made the same day with the same materials, but each have to be set-up seperately to get the best performance). That is where knowing how to tune and diagnose problems comes in handy and neccessary. If your bike has a new top-end and everything else (carb, reeds, ignition, crank/tranny, air filter) is in proper working condition, then start looking at the fuel and needle clip position (may be a little lean at 1/2 throttle-move the needle up-clip in the middle).
Sly