There's a diesel motorcycle under development, but it's not being made by Suzuki in Japan or BMW in Germany. It's being developed by a group of pensioners who call themselves the Gray Eagles, an informal collection of retired engineers and executives from Harley-Davidson and Outboard Marine. And if that doesn't strike you as out of the ordinary, the engine is not being developed from scratch or being retrofitted from another application (like the ThunderStar 1200 TDI) – it's being converted from a gasoline engine.
The Gray Eagles started with an '88 Harley-Davidson FXRS and converted its V-Twin to run on diesel, fitting it with a turbocharger and electronic fuel injection. Karl Nilson, one of the team members, was once in charge of Harley's "Nova Project", a program to develop a unique 150hp six-cylinder engine in collaboration with Porsche. That project was shelved in the early 80's due to budgetary constrictions after $15 million was invested, but Nilson, along with his fellow Gray Eagles, hopes to see diesel bikes on the road during his lifetime. The diesel bike is being presented to potential customers such as Harley-Davidson and even the Pentagon, who already run some dirt bikes on the same diesel the army uses for its tanks, jeeps and trucks.
(You can check out a video of the turbodiesel chopper by clicking here.)