Well, this is interesting...  Some mechanically-inclined guy decided to do something really new with his Harley Fatboy -- he converted it to run on bio-diesel!

Now, if only he could figure out a way to do it that preserved the fine looks of the v-twin motor that the Fatboy normally has, he’d have a real money-maker on his hands. 

As is, I think it’s a really cool experiment...  I wonder what the differences are in performance?  Typically, it’s harder to get high-performance from a diesel than with a gas engine.  Don’t believe me?  Watch this recent track test by Top Gear (awesome British auto TV show) of the BMW 535 diesel vs the gas-powered version of the same car: