TOPIC:

After I shut my engine off, I notice that gas sometimes starts to leak from around the air filter(individual pod), what causes this? I've also noticed that if I turn the petcock off, the leaking seems to stop.

13thlevel wrote:

After I shut my engine off, I notice that gas sometimes starts to leak from around the air filter....

Your needle/float valve assembly in your carb bowls needs attention. Unless you turn off the fuel supply, then the needle valve is the _only_ thing that controls/stops fuel flow into the carb bowls. The fuel that you are experiencing is coming from a over-filled carb, or two, or four.
The floats themselves are usually not the problem. It is usually the needle and/or seat.
You need to keep a close check on your crankcase oil level as it is common for gas to leak into the crankcase, thereby over filling it. That fuel comes all the way from the carbs, when the problem persists.