Motorcycle Repair: Fuel Starvation, condenser coils, fuel starvation

Question
How can you run a check to see if the engine is in fact  getting fuel?   I've got a 72 Yamaha xs 650...just rebuilt the engine, new points, condenser, coils,pistons, cam chain, replaced float bowls on carbs, new needle valves, main jets and pilot jets....checked timing, set valves...getting good spark to both cylinders, bike will start and run with one or two kicks, but only running on right cylinder, plug is firing, but when I pull it looks just like when i put in in...not wet or showing any signs of ignition....I've looked at everything I can think of...fuel is getting to the carb...just not sure its getting to the engine...is there a quick check to fix?

Answer
Dwight,

-make sure the compression is equal on both
cylinders.
-Is the carb filling with fuel?
-Try some wd40 or carb cleaner in the intake
and see if it fires on that.
-Is the rubber slide diaphragm okay, no holes
or tears?
-Make sure the carb slides are not sticking,
and are all the way down.
-Check the intake rubber for air leaks.
-Back off the idle screw on the right side a bit.
-Switch spark plugs
-Switch coils.
-Check choke.
-Have the float levels been set and are the floats
okay, no pin holes?
-Hold your hand over the left carb mouth and see
if you can feel any vacuum when cranking the engine.
It needs some vacuum to pull the fuel in.