Anchorman: The Legend of Ron Burgundy
Might be a V twin Yamaha, but then again I can't see a second exhaust pipe and it might be smaller single cylinder bike being used for the stunt. Looking at the thumb pic the style of front wheel spokes confirms it is a Yamaha - I think.
Hilarious scene. Flying burritos, dogs being punted off a bridge, Ron oblivious to reality. It has it all.