July 18, 2005 The concept of a diesel motorcycle is not one that
has occurred to a lot of people – at least not many have thought
about it for long because despite a rich century of innovation in
motorcycling, only a handful of diesel motorcycles have existed
and until very recently, they have all been utility vehicles –
bikes designed to get great economy on fuel of questionable quality
in rugged and remote regions and said diesel two-wheelers had no
As we all know, diesel technology has come a long way in recent
times and now the sans-sparkplug engine promises a renaissance thanks
to its low emissions, good power output and low consumption ...
and like so many aspects of technology, it was the muscle of the
military dollar that brought the world's first modern production
diesel motorcycle into being.
In the utility area of diesel motorcycles, one marque seems to have
been synonymous with diesel motorcycles –Royal Enfield–
the marque manufactured diesel motorcycles both before and after
its move from Britain to India, and as can be seen from this web
page, people just seem to like the idea of shoehorning diesel engines
into Enfield frames.
On top of that, one of the most utilitarian motorcycles of all time,
the Russian Dnepr, is still offered with a HATZ-Diesel engine, and
there is a small but enthusiastic group of diesel motorcycle enthusiasts
who manufacture their own motorcycles using diesel engines of all
There’s also a strong following for the diesel motorcycle
in Germany, some of which are producing impressive prototype motorcycles
such as this Peugeot-engined Kawasaki. Hayes Diesel Technologies
But despite this strong groundswell of interest, there is currently
only one modern production diesel motorcycle - a Kawasaki KLR650-based
machine which is remanufactured with a diesel engine for military
purposes in response to the new NATO requirements of "One battlefield
fuel" with that one fuel being diesel. An initial order for
522 diesel motorcycles has already been placed by the US Marines
and keen interest is being shown by the US Army, the UK Ministry
of Defence and other NATO forces.
A unique technology partnership between Cranfield University and
California-based Hayes Diesel Technologies (HDT) created the
bike – the first bike of any kind with a purpose-designed
diesel power unit.
John Crocker worked alongside project leader Dr Stuart McGuigan
of the Engineering Systems Department, Cranfield University at Shrivenham,
Oxfordshire to design the diesel power unit.
The challenge was to come up with a low technical risk design that
was sufficiently light and powerful, and with an engine speed (RPM)
range wide enough to give the level of performance required for
use as a tactical vehicle.
John said: “The motorcycle also had to meet strict NATO requirements
for all armed forces to operate their entire inventory of vehicles
and powered equipment on either diesel fuel or aviation grade kerosene.
“This capability has major logistic advantages in obviating
the need to carry other fuels to battle. And their lower flammability,
in comparison with petrol, also greatly reduces fire hazards.”
The engine configuration is a liquid cooled, normally aspirated,
584cc (36 cu in) double overhead cam single with four valves per
cylinder. Diesel fuel supply is through a special Fuel Injection
unit and single injector developed specifically for the task and
the Kawasaki-based combat bike produces a respectable 28 bhp at
5500 rpm with meaty flat power delivery from 1500 and 7000 rpm.
Unlike its gas-guzzling counterpart, the engine has multi-fuel compatibility
and can use commercial diesel (inc low sulfer fuel), NATO Military
Spec Diesel Fuel, Bio-Diesel (B20 or B100), Aviation Kerosene including
JP4, JP5, JP8, and AVTR and plain old Kerosene.
And it’s a real 28 horses too – the bike recently set
the world’s first land speed record for a diesel fuelled motorcycle.
Fred Hayes, founder of HDT, who was in the saddle at the world famous
Bonneville Salt Flats , Utah, said: “The event was marred
by rain the previous week and by poor track conditions, which limited
the top speeds due to soft, wet salt. The bike was officially timed
by the AMA at 85.466mph, against our calculated top speed of 86mph
with production gearing. The calculated speed was at sea level (4350ft)
on hard pavement. We’re delighted with the result. If we’d
had an option for gearing and more track time, we may have broken
the 90mph barrier.”
Fred does not rule out that the motorcycle may be made available
for the consumer market. “Although the motorcycle is about
20-30% more expensive than a comparative conventional motorcycle,
there would be cost savings for riders and environmental benefits
in that the diesel motorcycle can do 110 miles per gallon - a little
over twice the range of a conventional motorcycle,” said Fred.
The bike was officially timed by
the AMA at 85.466mph, giving it the
World record for a motorcycle
with diesel engine.
John Crocker and the HDT Diesel
The engine configuration is a liquid
cooled, normally aspirated, 584cc (36 cu in) double overhead cam
single with four valves per cylinder.
The motorcycles lining
up at the end of the production line at Hayes
Diesel fuel supply is through a special
Fuel Injection unit and single injector developed specifically for
the task and the Kawasaki-based combat bike produces a respectable
28 bhp at 5500 rpm with meaty flat power delivery from 1500 and