Recently had the exact problem, bike would only run with choke on. I wound up pulling the main fuel line "which feeds the carbs" and ran hose into a jar. For some reason It was like I had to prime the fuel pump. After two or three attempts of turning the key on and off, the fuel pump began moving fuel. I then reconnect to carbs and was able to move on to the next phase. Again same issues with running poorly, bike sat for 6 to 9 months. Did the seafoam enima and currently about halfway through a tank of fresh gas/seafoam mix. Bike is slowly coming back to life but honestly with only about half of tank burned.... it's about 85% there.