Carb sync

I had bike to local shop to have carbs synchronized. Not sure it was done properly. Plug fouls only one one side. Carbon fouls real bad. I suspect fuel mixture problem. Not sure if they new what they were doing. How do I go about doing the carbs myself?

This is covered if you google how to make a homemade manometer filled with atf in a clear hose from the hardware store. Good luck.