Fuel problems

I just bought a 92 seca and have ridden it less than 15 miles and I am having a problem. I noticed a puddle of gas on my garage floor coming out of my exaust pipe. after much examining I took my oil cap off and it was full of oil. I drained the oil and all the gas out of my tank emptied into the oil pan too.

I took my gas tank off and the last bits of the gas came out of my petcock. should gas be able to come out of the petcock like that, I thought it had some vaccum thing that was supposed to let it come out. Is this a problem with a carb instead, The bike was running fine before.

So what do I need to do before I attempt to start my bike again?

 

First thing to do is change oil and filter. Second is to rebuild the petcock or replace it. The diaphragm is torn and leaking or the oring on the plunger is not seating. Either way rebuilding or replacing the petcock is necessary. Third problem is that one or more float valves in the carbs are not seating and allowing the fuel to overflow into the intake and fill the crankcase. This can be taken care of later but should be done. The petcock is what should be done first.

 

I took the petcock off today, seemed to be some debris in there but anyway cleaned it up, checked the seals and put it together. Its back on the tank and I wanted to make sure, when it is in on no gas leaks out of it, when its on prime gas pours out, and in reserve no gas comes out, is this all correct?