Fumes and low MPG

This isn't a KZ per'se however its a kawi, someone may be able to help.

The other day was hot at the 50 mile charity ride. Average speeds were between 35 and 15 mph... toward the end of the ride my 98' Vulcan 1500 temp light came on. This was half expected to happen as it was very warm.

I gave the bike some time to cool down and the temp light went off and the bike was cool again.

As I pulled into my drive way, I was in first gear with the clutch pulled the bike idled really low and died. So I started it back up as long as I give it a little gas it's perfectly fine, but as soon as I let off the gas it will idle low and die. So I turn the idle up a little and its fine. (note: I barley turned the idle up at all.. just enough to keep it running)

The problem now is that when I come to a stop I can smell gasoline burning the fumes are almost nauseating and I can noticeably see a change in my MPG.

Any ideas? This Bike is a 4 speed carbureted 1500

Just a wild guess, but perhaps your petcock diaphram is leaking. If it is vacuum operated, then gasoline may be sucked into the cylinder where the vacuum hose is connected. This might explain the poor idle and MPG. Also, there is a small vent hole in the side of the petcock to exhaust the air as the vacuum opens and closes the petcock. Gas may be slowly leaking out that hole, thus explaining the smell, in addition to the exhaust smelling rich.
Don't know about the overheating.

Are you sure the bike is firing on all cylinders? Have you checked the spark plugs?

KRB)