He was riding a motorcycle and said "check THIS loser out hahahahahaha" while going past me, with his gf in the back seat.

I tracked him down eventually and spat in his face, he heavily flinched and looked shocked and scared. His flinching meant it just grazed his hair as opposed to landing square in his face. He didn't do anything and I kept jogging. He is 5'7ish while I am 5'11. I then disappeared down a dead end street, saw him from it on his motorcycle, then went back out and put in a lot of physical effort to get home quickly.