So on my bike there is the petcock line obviously going into the fuel pump. But there are two other nipples on the rear of the tank, neither of them are connected to anything and I can't see to find lines for them to be connected to. Bike runs fantastic being as it only has 7k miles on it. But it acts like it's out of gas when it gets to about 1/85th tank and I'm wondering if one of these hoses might be a vacuum? Let me know!

 

One of them should be a breather that lets air into the tank so fuel will flow out. The other should be an overflow, in case while filling the tank you put in too much, the same overflow hole also lets water escape from washing the bike or it left out in the rain.