This is my first panhead and I couldn't find too much info on the subject. I just got her running a few weeks ago.
Ive been trying to get her up to temp to tune my carb and just enjoy the sound of this amazing machine. Yesterday after running for only about five minutes I heard some pretty significant sucking from the vented right gas cap. I also saw what appeared to be steam. Is it possible that in this short amount of time my engine heated the gas tanks up to cause this pressure suck and almost boiled the gas?
I get that it is an air cooled engine and would do much better on the move to regulate temp. But shouldnt i be able to run it for a few minutes in the driveway?
Timing and tuning is on point.
Any suggestions on what could be going on here? Is the top of a oanhead hot enough to cause that kind of heat to rise to the gas tank?
Yall are amazing, thanks again.

 

The cap has a vent its clogged so as the gas being used is dropping in the tank it creates a vacuum - most times the bike stops while riding it

now i have seen gas boiling in the fuel tank Indian not a Harley - and yes it make a wheezing sound till you remove the cap

if you let it idle long enough to get the gas to boil - that motor is not going to last long -

only thing cooling it is the wind from riding - dont do that again