Built a few bikes in the future, have you? Arrest the illegal time traveler!!!
On to the topic (was it time traveling?). To get the most out of your engine, you will need a dremel to clean out your ports/transfers and match the case to the jug. Get a bigger carb and a proper expansion chamber, such as the mz65. You'll want to get your squish gap set right and a better cooling high compression head.
Edit: forgot to mention properly balancing your crank, that's a big one that prevents high rpms.