07/04/2018
A Brief History of Diesel Motorcycles
The first documented use of a diesel engine in a motorcycle was by Dutchman Jan Dopper who installed a Brons diesel engine into a bicycle he'd been given in 1904. The Brons engine produced a modest 2bhp @ 700rpm. Jan Dopper improved the machine by creating a new frame of his own design and then in 1910 made a diesel tricycle. In post-war fifties Britain some prototype diesel bikes were made based on Nortons. The British used to quite enjoy their reputation for being eccentric and were not at all offended by the song “Mad Dogs and Englishmen Go Out in the Midday Sun”. The first “mad Englishman” to build a diesel motorcycle was a gentleman named Tony Sidney from the coastal holiday town of Brighton. He created a 500cc aluminium single cylinder diesel engine with a cast iron head and fitted it into a Norton.
The use of aluminium helped keep the weight of the engine down although the engine was fitted with high tensile steel reinforcing rods from the crankshaft to the cylinder heads to ensure adequate structural strength. The engine produced 10-14bhp @ 4000rpm with a nice amount of torque and a top speed of 55mph. The bike was very capable climbing hills around Brighton but acceleration was lacking, the bike sort of “gained momentum” rather than really accelerating. Kick starting the bike was “possible” with the compression release lifting the valves, but on cold mornings the bike needed to be push started. Preferably by a car. The engine also had a large exposed flywheel which was rather hazardous to ones left ankle although quite convenient for setting up the timing. Only four of these prototypes were made.
The next “mad Englishman” was Freeman Sanders who called a town called Newlyn, Cornwall his home. He also chose a Norton for his prototype and his engine produced a quite respectable 18.5hp @ 4500rpm giving the bike a top speed around 70mph and miserly fuel consumption of around 140mpg. (For those interested this bike was featured in “The Classic Motorcycle” magazine of September 1992). Sanders' bike was based on a 490cc Norton with the only modifications being to the cylinder head and barrel. To avoid the need for extensive modification of the engine's bottom end Sanders kept the compression ratio down to 11.8:1 but still managed to have a viable working diesel. Although his motorcycle did not get past the prototype stage Freeman Sanders went on to design engines for Lister. The first company to actually roll diesel motorcycles off a mass production line were Royal Enfield of India. Royal Enfield are said to be “Built like a gun, fast as a bullet”. No doubt the Royal Enfield diesel was solidly “built like a gun” but with its 325cc diesel engine it was certainly no “bullet”, not even a very low velocity one.
Back in 1992 a company called Sooraj Automobiles located in Saharonpur in Uttar Pradesh province of India began installing 325cc Greaves Lombardini diesel engines in stock Royal Enfield Bullet motorcycles. This bike was called the Ta**us and was sold through the established Royal Enfield dealer network in India. Among the models of the Ta**us was a bright yellow one with a novel crash guard aimed at agricultural and government use. The engine of the Ta**us had an 18:1 compression ratio and produced 6.5hp @ 3600rpm with 11.1 lb/ft of torque. Claimed fuel mileage was 190mpg (US) at 25mph. As we said, a very low velocity “Bullet”. Later in production a 436cc diesel Ta**us was made which was called the Royal Enfield Lightning and which featured an electric starter. The manufacture of diesel Royal Enfields in India got people in the UK and Europe inspired and there have been quite a number of people making diesel conversions mostly of Royal Enfields.
Currently diesel motorcycles are being mass produced by Hayes Diversified Technologies (HDT) for military use. The HDT M1030M1 is based on a re-modelled Kawasaki KLR650, which is fitted with a specially designed 584cc diesel engine and boasts a top speed of 90mph. The project was jointly undertaken by Cranfield University and HDT. Fuel consumption is 96mpg (US). The bike is already being supplied to the US Marine Corps where it is known as the M1030M1 JP8/Diesel and is also being supplied to Britain and NATO where it is designated the M1030M1E AVTUR/Diesel Military motorcycle. The civilian bike is expected to be called the D650A1 "Bulldog” but due to pressure of military sales it is not available yet. Hayes introduced an upgrade model of their diesel motorcycle in 2010. This model is the HDT 1030M2 and has a 670cc engine with multi-fuel capacity.
There are a few companies with production bikes in the planning stages. We will have to wait and see if these vehicles ever pass the prototype stage.
Material source: Silodrome
