overflow of my carb

[Buffalo400]

I can see the gasoline fall down by the small black bowll, 1 drip each 4 sec. It's the overflow? What's the problem? my bike made some backfire somtime.... I run stok air box, pipe, filter k&n....
Thanks

[H440exconfused]

float stuck, or trash in the needle seat, removed the carb, removed the bowl, and check the float and clean out carb and bowl with carb cleaner.