I had a '99 Valk Interstate and I wanted to see how far I could go on a tank...............big mistake, sucking fuel from the bottom of the tank introduced some foreign particles into the carbs. It didn't run too good and by lightly touching the pipes I could tell a couple of cylinders were colder than others. To make a long story short after a couple of tanks with carb cleaner through it, it got better. Your problem is alittle different, after sitting for awhile your low/idle jets have gotten gummed up from old fuel...............if you are lucky try the above it may clean out those little guys. I have a couple of old CB750/550 and when I screw up and let them sit too long I get what you describe, need choke to idle. I pull the carbs drop the bowls and spray carb cleaner in the jets and carefully run an acupuncture needle down it followed with a little shop air, this works every time. I have learned to use Sta-bil in every tank and ride as often as possible. Good luck.