Personally seafoam is a preventive item, not a maintenance item. There's no substitute for a proper carburetor refurbishing, which is far more than a simple cleaning, which after 2 years of sitting they would need, just for piece of mind.
I'm afraid to ask how much they would charge for it., check out @
ducatiman his prices are affordable, a lot more cheaper than a dealership I'm betting.
https://www.ninjette.org/forums/showthread.php?t=226815