There is also a method using clear plastic tubing on the carb drain screw that will tell you what the gas level is at. Just did some searching and found an easier way to do this. I guess I need to drill a small hole on the float bowl drain plug, insert some clear tubing in it and then attach the carb back to the gas tank. Switch the fuel on and let the carb fill up with fuel while holding the clear tubing above the float bowl. My goal is too adjust the float until the fuel in the clear tubing goes up the where the gasket in the bowl is. Problem is I don't have a spare drain plug and I dont think anyone sells one locally.  I think I saw a picture on the yamaha  xj  forum site.  I searched on this  (clear plastic tubing  float level).