Start by changing the color of the bike some more, looks like it's almost the exact same color as the suit he's wearing making hard to tell character apart from the machine.
And you can use the rest of the frames to make the hair move a bit more fluidly.
I think that making the bike move one pixel lower for one frame might do the trick, but i'm not too sure. Maybe using two frames would work better..?
Experiment with that.