Motorcycle Repair: Yamaha Roadstar 2000 fuel overflow, fuel vapors, traffic jams

Question
When riding in a hot day and stopping at traffic jams, my bike seems to run quite hot and then fuel starts overflowing on right side where my air filter sits?  Then when traffic clears, the bike will not answer to throttle and it will die.  It takes a couple of seconds starting before the bikes starts again, then the bike will work fine until the next stop, if I stop for too long, again the same problem.  But only on a hot day.  On cool days, the bike will run fine.

Answer
Hi Dennis,

Sorry for the wait.... I've been working OT lately.

I suspect the hot air temperatures may be causing a build up of fuel vapors inside the fuel tank that normally would be vented to the airbox. The fuel evaporative system my be defective causing the problems. The symptoms may be simply caused by a pinched vent or vacuum hose, obstructed vent in system, varnished needle (float) valve, or electrical including throttle sensor problems.

I would need to perform several checks via process of elimination to accurately diagnose the problem.

These symptoms are common following periods of non-starting or storage.

Respectfully,
Mark Shively