cool idea, just for sake of helping out...It looks like the light source is from the left to right on the backround image, and almost from above. The shadow should be on the other side of the bike and not so long. Look at the tufts of grass in the backround image, the shadow is cast on this side
A fat ... man on the Big Bike really funny and great show of Freedom
Sparky-the-Biker needs some Sun on his lily-white exterior.