The armed forces of most NATO countries are committed to a ‘single fuel’ policy for all battlefield equipment, based on diesel fuel in peacetime and avaiation kerosene in war. Motorcycles will shortly become the only land vehicles unable to comply with this policy.A programme has been undertaken to establish the feasibility of a diesel-powered motorcycle offering the all round on/off road performance required for military duties. A demonstrator motorcycle having a compact, high specific output naturally aspirated engine, capable of running on the specified fuels, has been designed and built. Evaluation by the British Army and US Marine Corps indicates that a production machine employing the technology used in the demonstrator would be capable of meeting the user's requirements.The paper describes the design approach used to produce the demonstrator machine, performance achieved and potential for further development. It is considered that, beyond the military sphere, there would be wider application for engines of this type in small all-terrain vehicles and portable power units, as well as for motorcycles.