The D.E.R.A. Military Motorcycle
To those who take an interest in matters Military, it's common knowledge that NATO has embarked on a one fuel policy due to the fact it's cheaper and safer to have all their vehicles running on the same substance, ie: diesel. Obviously they had a slight problem when it came to motorcycles and both the British and United States Army's have embarked on various ventures to see how feesable it would be to convert existing bikes to diesel. The British converted a Royal Enfield engine to run on diesel and invited Fred Hayes of HDT over to try it out. Things went very well and R.M.C.S. landed the contract to design a completely new engine for the Marine Corps. After 2003 Petrol will no longer be allowed aboard U.S. warships and so the Corps needed to replace their existing bikes with something that used an alternative fuel.
This D.E.R.A. / R.M.C.S Bike (above) produced in1995 has an Enfield Bullet crankcase (beefed up) and a specially made top end which boasts 4 valves! It is of 547cc and produces between 16-18 BHP. Diesel injector is a modified unit from a car while the gearbox has but 4 gears. Apparently the engines flywheel is lighter than you'd normally expect to find on a diesel. The bike clocks 156 MPG @ 40MPH and 184 MPG @ 30MPH. The engine is mounted in a frame supplied by Eric Cheney. This bike easily pulls away from 250cc petrol bikes on cross country runs according to test riders.
source: http://www.dieselbike.net/royalenfield/royalenfield.htm