a carb leaking by itself may not cause a no start, but the problems it causes may....too rich, fouled plug, if left to sit with petcock on may have the bottom end flooded.
are you getting spark, new plug, checked reeds, deleted tors ???
click the bottom link below my sig pic \/ for info and links on troubleshooting and deleting the tors
reeds are petals that open and close to allow fuel/air from the carb into the engine, and close to keep it in there, they are located between the rubber intake the carb connects to, and the cylinder.....remove carb, remove the 4 bolts that hold the intake in, and pull the intake and reeds out all as one, you'll see 4 fiberglass or carbon fiber reed petals, they should be in good shape, no cracks or chips, and sit nice flat and tight to the reed cage.
tors is a throttle overide system in case your throttle should stick, not sure if it ever worked ? it luvs to fail and cause mayhem, it is best deleted. it includes the large box on top of the carb, a switch in the thumb throttle and a brain under the hood (3 wires)
here's the deletes for pre and 03+, use whichever yours is...88-02 or 03+