Durr , just re read the post it's coming from under each carb , was the fuel shut off for the 12 months you left the bike ? Could the fuel pipe from the pump have deteriorated and split , it seems strange that all 4 carbs have suffered the same problem at the same time , if it is each carb you will have to figure out the place the fuel is coming from
I recall reading a few of your posts about removing carbs and replacing seals/orings and replacing inlet rubbers , could you have missed something when you refitted them ??