This is lengthy post I wrote on a different forum that explains what is going on with the gas dripping, and my experience trying to solve the same problem. You don't have a gas leak problem, you are experiencing a condensation condition.
This long post explains everything:
I am a 2008 Jackpot owner and have experienced the same condition as your bike on many hot days sitting in the sun occasions. I have done extensive research on this and would like to pass along my findings and suggest perhaps, you do not have a problem. Let me explain.
I too purchased my 2008 Victory with single digit miles, and the factory gray gas cap installed. If it sat in the sun, gas level didn't matter, it dripped. I viewed your image of the gas drip spot; yep exactly the same as mine. Would never do it in my garage even if it was 95 outside and very hot in the garage. Even during winter storage I put a block under the kickstand to keep it more upright in my garage for added space. I filled the gas up into the filler neck as per the ownerís manual. It sat like that for months with a tank full enough the touch the cap, result, no leaks. My intention at purchase was to replace the gray cap with a chrome one, I thought this might fix the problem, NOPE still did it.
I have experienced the overflow/overfill condition when I filled the tank while holding the bike straight up. I then rode only 2 miles and parked at a friendís house and it vented gas as the tank warmed up. But this condition is very different than what I believe you and I are seeing when we park it in the sun. It was a semi-steady flow of gas and it was very evident to me that I overfilled the tank and it was expanding from heat and pushing out excess liquid. As you stated it will do it with a 1/2 tank and perhaps even less. That would exclude the overfilled gas expansion theory, as 2 gallons of gas would not expand so much to push liquid out the cap and down the vent or drain tube.
I reviewed the parts breakdown of the gas tank and drain system on the Victory web site parts pages. The hole on the left side of the cap well is a drain hole, and the hole on the lower right side of the cap well is the vent hole. The cap has an orange rubber tube that mates to that vent hole. The drain tube, and vent tube meet at a "T" fitting and become one, that one tube is the tube you see gas coming from on the left side of the bike by the oil filter. If gas is coming out of that tube that means its not obstructed. If you only have a 1/2 tank of gas, and gas is coming from that tube and we ruled out that 2 gallons of gas will not expand enough to vent liquid out of the drain tube, then it can't be pushing liquid gas out the tank and down the tube. So, if you see gas fumes exiting that tube that means your cap vent is working properly, so where is the gas coming from? That was my question also.
With all that said, I contacted 3 Victory dealers in the Seattle area to address the same questions and concerns you have inquired about. I wanted to know what is wrong with my bike. The 1st said I don't know bring it in. The 2nd and 3rd dealers stories were almost the same. They told me the condition I am experiencing is; when the bike sits in the sun, the sun heats up the gas causing it to vent fumes. As those fumes travel down the tube they cool and turn back into liquid and drip off the tube, not out of it as a pure liquid running down the tube would. They assured me nothing is wrong with my cap and tank vent system, it was operating as it is supposed to and it is just something they (they being 2008 and newer Vic's) do. Still not satisfied with 2 out of 3, (cuz I'm an aircraft mechanic and I'm weird like that) I needed to know for sure. I thought of the hottest place I could park a Victory in the Sun..... I settled on Phoenix AZ. I again contacted 3 Phoenix area dealers, all three echoed the same story. If you only have a 1/2 tank of gas and you see fuel fumes exiting that drain tube then your vent system is working properly. They all three confirmed the hot fumes cooling and returning to a liquid theory, additionally they all three stated the 2008 and newer models "all do it". That was good enough for me, I was convinced, that is just what they do.
After reading the posts to this topic; checked old cap, checked old tank, no problem with either, drip still there. Replaced cap, drip still there. Replaced tank, drip still there. So lets see, old tank and cap did it, new tank and cap do it, dealer can't figure out what is wrong. Seems to me the chances you got two bad caps and two bad tanks, and mine does the same with a new cap, and 5 out of 6 dealers stated they do this drip thing in the sun. The chances all those repairs didn't fix it, and all those dealers are wrong, in my opinion would be very coincidental and highly unlikely. As I first stated, might be because you do not have a problem with your KP. However, if your dealer is able to fix this please let me know what they did.
Hope this helps.
2008 Jackpot, Boardwalk Blue.