Gas is leaking from the peacock valve under my gas tank seems to be coming directly from the bottom,what could cause this?

There's a gland nut that holds the petcock into the tank and pulls it up against the seal. Try tightening the nut. But, in all probability, it's the vacuum diaphragm in the backside of the petcock.

Harley went to a vacuum operated petcock in 1996 and they've been a pain ever since. The diaphragm gets a small hole in it and leaks gasoline or quits opening leaving the rider stranded.

Now, You can repair the petcock if you wish. Get a large funnel and an empty gasoline can. Loosen the petcock and allow the fuel to run out around the nut, catching it in the funnel and directing it into the gas can. Once empty, take the fuel line and the vacuum line off the petcock. The vacuum line is the small line on the backside. Take the petcock out of the tank. Look on the backside and there are four small screws. Take them out and carefully take the back plate off the valve. You'll see a diaphragm, a spring, and needle. Take the diaphragm and hold it up to the light and gently stretch it. You'll probably find a hole. You can get a replacement diaphragm from you local dealer. Reassembly is the reverse of disassembly.

Personally, I'd rather replace the vacuum operated petcock with a high quality manually operated petcock such as Pingel. The OEM petcock will fail on you and leave you stranded with a full fuel tank and an empty carburetor. The Pingle won't. Just install it, connect the fuel hose, and plug the vacuum hose.

Good Luck
Steve