When I first came across this article from Autoblog I thought it was very creative using an airplane engine in a motorcycle. After further reading I realized the engine was roughly 410 cubic inches. The first image is deceiving and you get a greater understanding of how to fit an engine that big on a motorcycle, you make the rest of the bike huge. Here are few more images from Autoblog showing just how huge this bike really is.
The bike is built by Clemens F. Leonhardt of Germany. The engine is from a old 9 cylinder radial aero engine and in the current configuration puts out 350 hp. The bike has a 3 speed trans with reverse because I am sure you would sweat a little pushing 870 lbs (current bike weight). He was going to use tires from a Boeing 767 but he was able to find a supplier who is willing to build custom tires for him. Future plans calls for making a few more for friends and maybe even building a side car. May we suggest a Mini?
Another project he has going is building a motorcycle with a single cylinder diesel engine.