mmm puzzler So you could have a fuel pump dying but before you get hung up on fuel issuse maybe you should check your spark plug wires. This might be a long shot but if they have developed cracks in the sheathing this could cause suporatic idle or a lack there of. A easy quick test is to spray a mist of water on the wire while the bike is running. If the plug wires are bad you will know right away
This is my good luck!!!