you know.. you check and/or clean the entire fuel pathway from the gas tank's cap all the way to the engine ..
it could be slow fuel flow from the tank.. or just a tiny bit of crap in the float bowl.. a clogged filter somewhere.. Work your way from one end to the other, cleaning and inspecting, 'till you find out where the problem is.
Something like an old, deteriorating fuel line and/or broken filter screens might clog it up again in the future so.. well.. if you wanna spend more time riding, do it right and you won't have to do it again.