Dodge Tomahawk
 

Dodge has a V10 powered motorcycle...the Tomahawk.
4 wheeler goes 300mph, all for $250K!http://www.allpar.com/cars/concepts/tomahawk.html

Styling exercise.
Not capable of turning much better than a dragbike (maximum lean angle of 15 degrees from vertical).
No actual speed calculations were done using hp/resistance, somebody in the development group simply said "holy crap, if the Viper does 185 with this motor, then this thing oughta do 400" and the number stuck.
The motor is required to suck its intake air thru a small snout that snakes thru the bodywork, restricting it from its original 500-horse rating an undetermined amount.
Actual "expected" speed if it still makes 500 horses is in the 260 range (a long way from 400 or 300).
Only holds 2.7 gallons of gas. Just enough to run 5 minutes wide open.

It's very cool, though.