A little constructive critique...Other than the downpipe, it looks a little flat to me. Maybe try putting a stroke around the girl and parts of the bike to help define them.
Also the boot looks like it belongs to Herman Munster. I could not image riding with those big clunky things on my feet. Bikes are a real chore and a half to draw convincingly, with all of the visible motor parts. Try adding some more shapes behind the the heads and pipes to help clutter up the empty solid grey shape that you now have behind the motor. Some hint of spokes would help as well, as it now looks like hubcaps. I personally dig chicks and hotrods.