i'm guessing the same. i had a similar problem when i got my 550 last year. it's not uncommon when they stood for a while.
if the tapping alone does not help, you can run the bike with fuel off until it stops, then tap each carb. that kind of sucks the carbs dry which can help dislodge more stuff.
you can also drain the carbs and take off the bowls while still on the bike to see if there's any debris in there and clean them out.
if it still keeps happening then you get crap from the tank into the carbs with the fuel. then it's time to either renew the fuel filter that's inside the tank or install an inline filter (which many people here will advise you against but can save your day in the short term). and clean out the tank, of course.