[Frank Lee]

You are darn lucky the lil guy has drums! Bike disks are sooo draggy.

At those speeds I wouldn't go out of my way to work on aero. Pump up the tires 5psi at a time and see what you think. Chain tension is critical; better to be a bit loose than a bit tight. Be sure to check tension while you are sitting on the bike, and roll fore and aft, checking at several points. Sometimes things aren't perfectly concentric and there may be a tight spot. Get each wheel up in the air and give it a whirl to make sure nothing is dragging.

Fix the carbs. You may not even have to disassemble; drop the bowls and take the air filters out and shoot carb cleaner in there. I like to blast the carbs with compressed air after doing that.