Start by opening the drain on one carb to see if you get a lot of fuel (a full float bowl will drain for 5-10 seconds with a steady stream, depending on how far you open the screw).
After closing the drain, turn on your key and listen for the fuel pump to click rapidly for about 5 seconds. If no clicking, you have a bad pump. If it clicks rapidly for five seconds and does not slow down, cycle the key off and back on - if it clicks for another five seconds without slowing down, you have a fuel supply problem - most likely the fuel filter, but could be intake screen in the tank, too.
If your filter is clean, you can just bypass the pump and ride the bike on gravity feed until you replace it. This is coved in detail in many other threads.
Goose