Petrol "gushing"

When I start my GPZ 900R the petrol comes gushing out of the engine directly under the front end of the seat. It only happens upon starting the engine but ALL the petrol comes out. Can anyone explain what this may be? I am thinking a leak in the fuel line or hose and not a faulty fuel tap due to the amount of petrol and speed at which it all comes out. However I am not too knowledgable in this area. I have contacted a mechanic who said he does not work on bikes of this age, so if anyone can help me as to a mechanic, preferably on the north side of Syney or Northern BEaches, I would appreciate it.
Thankyou.
Patboy
Thankyou.
Patboy