I'm sorry, I am not familiar with this condition ... I have not experienced it with a motorcycle. I am familiar with "vapor lock" in cars ... this problem is mostly solved in modern cars.
Vapor lock was a condition where the fuel vaproized in the fuel pump and made it impossible for the pump to deliver fuel to the carb. This condition always presented itself on a hot Saturday afternoon while the family was out for a drive. Ironically, we were out for a drive to cool off! (In the days before AC) Dad would stop to get gas and the heat in the engine compartment would cook the fuel in the pump causing the dreaded 'vapor lock'. The fix was to cool the fuel pump. One very popular way was to slice a grape fruit in 1/2 and put it on the fuel pump. The juice would evaporate and condense the fuel and the pump could then pump again. Today, most fuel pumps are in the fuel tank and rarely get hot in the trasitional sense.
I would be very interested in learning more about this problem and its solution. When you find it out, please post it on this thread.
I dont understand 'holona1's solution. Maybe there is an answer in the response - I didn't get it. I am not degrading holona1's response, just saying I don't understand it.
I know there is a Yamaha Rider Club at http://www.yamahaclub.com/
. Being a Honda owner, I am a member at the Honda Rider Club. If the Yamaha club is like the Honda club ... what a rich source of information. You may want to poke around over there to see what you can see.
A few random thoughts in no particular order ... you could fill your bike at home before you go on a ride ... I don't know where you live ... though dangerous, you could fill the tank with the engine running ... though I don't recommend this
except in the extremest of emergencies ... most motorcycles can go about 100 miles on a tank of gas ... I dont know about you ... my rear end has about 100 miles of endurance and it is time for a break!!! Maybe you should take a break at 75 or so miles (on longer rides) fill the tank and fill your tummy at the same time ... maybe smell some roses along the way.
I'm sorry you are having this trouble ... did the previous owner have any words on how he or she addressed the problem? What about the Yamaha shop? Jump starting is not a glamorous solution though effective most of the time. Itis better to eliminate the problem.
Ride safe ... and thanks for your interest in FixYa.com