Re: The vibrations are KILLING me
All single cylinder motors vibrate like paint shakers at certain rpm. All you can accomplish by balancing your motor is to change the rpm where it vibrates the most. It's impossible to balance for all speeds. For cruising around on a motorized bicycle the trick is to gear your bike tall enough to not be running in it's worst vibration zone when you get it up to battle speed.
China Girls aren't racers, so they're not balanced to be smooth near red line. Mine all feel smoothest closer to maximum torque.