If your airhead has been sitting for any period of time and one or both cylinders are not wanting to idle or run well at really small throttle openings there is a quick fix. Simply remove the float bowls and unscrew the idle jet. Spray through it with some choke and carb cleaner. After you put it back in the bike will likely idle great.
2012 Kymco GT300i
2009 Piaggio BV500 Tourer