I do not know about your bike, but when the fuel tank is hot it is venting out fuel from the top vent which in turn goes into the built in charcoal canister inside the airbox. The canister then vents to the purge valve then down a hose to the intake manifold where the gases are consumed while running. With the purge valve always opened when stopped there are fumes building up in the intake tract.
My dad, who has 8 times more mechanical ability than me (thanks dad!), routed a vent tube from the charcoal canister out the airbox and down through the frame through the ground. For now it looks like the bike is starting correctly, I will take it for a long ride this weekend and let you know if it worked. Perhaps this might solve your problem as well?