I just purchased this bike. This is my first street bike so please forgive the ignorance. The question that I have is about the petcock. The elbow on the right side of the picture slides in and out.  Why is this? the bike was sitting for a little more than a year without leaking. I pulled the tank to drain the gas, change the air filter etc. I noticed a little seepage when i put the tank back on, but no gas seepage since i pushed it back in. (It is snug when in) I'm just worried that it will come out while ridding.

Yeah, I'd fix that if I were you.

I'm not sure how though.

OK found out that it is supposed to come out. people do one of two things. they either tap it out for pipe thread or jb weld it. Mine is not leaking just pulled it out a little when I pulled the tank. Being a vacuum system it wont come out while riding 

That part of the system is not under vacuum. Only the diaphragm in the back of the petcock is is at negative pressure. 

Since you don't have a fuel pump there is not much pressure, but your fuel nipple is more likely to leak when you have a full tank.