I had the pleasure of seeing the Dutch built Thunder Star for the
first time at the 2005 German Diesel Motorcycle Rally in Hamm. On
arrival we'd been told by the organizers to expect the appearance
of some ground breaking machines and were not disappointed when firstly
the 'Edimo' and then a second Smart engined machine rolled up.
But it was very late in the day before the Thunder Star blessed
this most unusual gathering of motorcycles with it's presence. At
around 10 am on the Sunday morning, a large van emblazoned with the
Star Twin motif wound it's way carefully down the somewhat misty,
tree lined lane which passes the entrance to Brauhof Wilhaus, an establishment
that has been the home of the rally for the past five years or so.
With the rally camp site looking decidedly empty at this late
stage, it was only the stalwarts that were rewarded with a glimpse,
and in several cases a ride, of this revolutionary machine. With the
Star Twin transport parked just inside and to the right of the main
entrance the crew preceded to off load the Thunder Star while all
about eyed this magnificent machine unblinkingly and with mouths gaping.
From this point on most of the conversation took place in Dutch,
a languages not too far removed from German which, of course, was
spoken by the locals.
One of the first answers to come across from the ensuing barrage
of questions was that the machines late arrival had been due to the
fact that Star Twin Motors were unable to get anyone to cover for
them in their shop the previous day. This had meant an early start
Sunday and a quick dash across the border from their home town of
Loenen.
With an ear towards the conversation and an eye pressed firmly
to my camera's view finder, I set about recording the event for DieselBike.net
as best I could. It's at times like these I envy the bigger and more
established publications who roll up with their own photographers
and expensive equipment. All I had was an absent brother nursing an
almighty hangover.
Now there was a time when the private bike builder would not
have at his disposal such construction aids as personal computers
and software like CAD/CAST but, I'm glad to say, times are 'a' changing,
as they say. When Star Twin owner Kees van der Starre decided to go
ahead with this project he wasted no time in drafting in Jeroen Bernart
who was able to create the machine in 3D.
Indeed, the CAD/CAST software was instrumental in designing
some of the engine castings and helped Bernart develop lightweight
and strong parts that make the Thunder Star what it is today, a very
reasonable 205 kg bike. We are told that virtually everything you
can see with the naked eye has been designed by Star Twin and that
internally, they have utilized both car and motorcycle parts. These
in themselves have been adapted, in the case of the car parts, to
be lighter, whilst the parts originally meant for two wheeled vehicles
have been made stronger.
Since the Thunder Star was first unveiled to the general public
back at the MoToRai Motorcycle Show in Holland, it will come as no
surprise to hear that the most frequent questions directed at the
bikes builders have been concerning the machines engine. This is,
after all, what it' s all about.
Nestling beneath the futuristic black and yellow bodywork is
a Common Rail, three cylinder, VW Lupo 1200cc diesel engine with the
potential to produce as much torque a Triumph Rocket 3. Like all of
today' s best diesel cars it boasts direct injection, a turbo and
an intercooler which, for the uninitiated, cools the incoming air
and thus increases it' s oxygen content for better combustion. The
transmission gives us 5 gears to play with but such is the torque
that one hardly needs them. This bike apparently pulls like nothing
on earth, wherever you are in the range. Surely it is this capability
that is at the heart of what diesel powered motorcycling of the future
will be all about.
Riding machines such as the Thunder Star will offer bikers a
wholly new power dynamic to play with in the form of roll on acceleration
figures to die for. Manufacturers have always kept a close eye on
their power to weight figures. Given the differences between the energy
delivery of both petrol and diesel engines, not to mention the differing
weights, a sea change in thinking is required here for those brave
enough to consider making such motorcycles.
Kees van der Starre is rightly proud to state that Star Twin
have produced probably the most advanced Diesel powered Super-bike
to date. With an engine that currently produces approximately 70 bhp
in its current state, Kees van der Starre has admitted to deliberately
keeping the bike detuned for a time after its creation but he has
said they will slowly increase the power until they have a very reasonable
100 bhp and generate around 200-250 Nm of torque. Kees has gone so
far as to admit that immediately putting all that power through a
dry clutch and chain drive might be a tad dangerous and that is why
they are increasing the output slowly. We agree.
When questioned about the style of the machine Kees stated that
racers were the most challenging and difficult machines to develop.
Star Twin chose this path because they know it is easier to transform
a racer into a tourer/road bike than visa versa.
When asked about a possible production version of the bike Kees
stated that while it was possible they may enter into negotiations
with another company or companies they were just as likely to produce
a small number of the machines themselves. But this would be unlikely
as the current machine is a true prototype and to produce similar
machines would be uneconomical.
If prospective diesel motorcyclists were looking for anything
else they may not be surprised to learn that the contents of the Thunder
Stars 18 litre tank would take them considerably further than if it
contained petrol. The makers claim a fuel consumption figure in the
region of 2.5 litres per every 100 km traveled. That' s approximately
150 miles to the Imperial gallon.
With the sky beginning to darken somewhat, firstly a Frenchman
(he of the Peugeot Kawasaki) and then a fellow countryman, Vim (he
of the Daihatsu BMW) took the machine out for short rides. After a
quick dash back to the tent I was able to fire up my Canon camcorder
and record Vim returning from his rather special and unique ride.
It was interesting to note that while the machine looked every inch
the racer, there was, at lower revs anyway, evidence of a slight but
distinctive diesel clatter' as the bike swung around and passed me.
I mention this not as any kind of criticism but more by way of notice
that this is just another one of the different characteristics that
bikers may have to come to terms with once going diesel becomes an
option. These kind of engines have a compression ratio of 1:16 and
at these kind of pressures injection mapping and sound proofing will
have to improved still further if the noise is to be banished altogether.
Not long after the last rider returned, Kees and his crew packed
up the Thunder Star and, along with the rest of us rally goers, said
their good-byes and set out on their long journey home.
In many ways the 2005 Hamm Diesel Motorcycle gathering was a
landmark event. Previous years have seen countless generator based
machines (my own included) turn up, but this year had been different.
For the first time not one, but three electronic diesel injection
motorcycles had made an appearance. And if that is not ground breaking
in itself, I don' t know what is.
Full marks go out to the organizers and all those who made it
happen.
SJS
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