well it has a vaccum tap so the fuel should only run freely from the tap when the engine is running so that must be faulty if it leaks all the time,the carb itself has a float a float needle and a float needle seat if a bit of debris get stuck in the neelde seat between the needle and where it seals it will leak out of the drain pipe thats on the bottom of the carb,take the float bowl off and have a look in there it can also be caused by wear to the needle or the needle seat also the float can have a split or hole that can cause it to fill will fuel and lose its bouyancy so it wont float on the fuel anymore shake it to see if you can hear fuel inside it.if so replace it.
adam bike doctor, September 2009
