What’s Cap riding…?

In the upcoming Captain America 2: The Winter Soldier, Cap is seen chasing someone down on a motorcycle. But, what is it? Hmmm. Ducati Monster made love to a Sportster and birthed this thing...? I've been trying to figure out just WHICH Sportster model it was, then I noticed a few tell-tale things on it that point it away from being a Sportie at all. Eh...? So, what are your guesses? Something one-off for the movie? Something upcoming? Something older that we just don't recognize? capsbike