| Diesel
and Bikes – Oh No !! Feature article by
Dick Henneman Ask any biker what things
they fear most when they’re out on two-wheels, and
one of the replies you’ll usually get is diesel.
So what if you carried three gallons of the stuff around
in your bike’s tank when you went off for a ride?
Wouldn’t it be like carrying the Grim Reaper as
pillion? Apparently not, if you have a military mind. Let
me explain.
When
a modern country’s armed forces mobilises for action,
one of the biggest problems that the planners face is
logistics. In ordinary language this means getting all
the supplies, equipment, fuel, munitions, etc, to the
right place at the right time to support the troops and
their vehicles wherever they get sent. In the old days
this meant food for the horses and the troops, and what
couldn’t be carried in backpacks or in a train of
wagons, was foraged from the countryside. But as armies
became more mechanised the range of supplies that they
needed increased, and when the internal combustion engine
came on the scene, fuel and engine lubricants became essential
for progress. This meant that you either had to cart it
along with you, arrange for stocks to be strategically
placed along your line of advance, or have very good delivery
system set up. Let’s face it, you couldn’t
expect to drive your regiment or battalion onto the local
petrol station forecourt, flash the plastic, and fill
the tanks up! And if that wasn’t enough, you needed
diesel, petrol and aviation fuel to keep the whole thing
going. It was a logistical nightmare. And it still is. But
the only vehicles that still need petrol are the military’s
fleet of motorcycles, so small but essential stocks of
this fuel still have to moved around in order to keep
the whole military machine purring along. Now just suppose
they had a bike that could run on diesel or aviation kerosene
. . . . ? Ah,
now I begin to understand.
Enter stage left the Royal Military College of Science
(RMCS) in the UK and Hayes Diversified Technologies (HDT)
in the US, who between them were tasked to develop a bike
that would run on either of the two fuels that make up
99%+ of military fuel supplies. If this could be done
without reducing the bike’s performance, then they
would have a logistical winner. And if they could improve
some aspects of the bike’s performance, then it
would be a win-win. Back
in 1993, the first steps were taken by RMCS to produce
a “feasibility demonstrator” based upon then
current diesel engine technology, to find out whether
this could be used as a low-risk development starting
point. This demonstrator bike used the crankcase and gearbox
from an Indian Enfield to keep costs down, and a rolling
chassis specially made by Eric Cheney. The results were
encouraging, and from this Dr. Stuart McGuigan and John
Crocker of RMCS went on to design a new engine, with development
and production being undertaken by Fred Hayes of HDT in
the USA. This machine used running gear from the Kawasaki
KLR650, a military variant of which was already in use
by the US Marines. The objective was to produce a high-torque,
high-revving normally aspirated unit so as to get the
most power from the size of engine, and the current version
delivers around 24bhp and 33ft lbs of torque from a 584cc
single cylinder unit that uses double overhead cams, four
valves and indirect injection. In the modified KLR650
frame, this gives a vehicle top speed of over 80mph and
a dry vehicle weight of 167kgs. Anyway, enough of the
numbers and the technology – what’s it actually
like to ride! I went over to the RMCS at the invitation
of Dr. Stuart McGuigan to check out the bike and to see
what it’s like to go into battle on two-wheels.
At first glance it looks like any other big single
traillie, but without the vivid colour schemes and stickers
that we’ve become used to. In fact, in it’s
olive-grey drab paint its almost as though it’s
still in primer and they’ve forgotten to paint it.
But in a battlefield situation, you don’t really
want to go out of the way to attract too much attention
do you? I presume that the paint doesn’t absorb
radar pulses as well – but you never know! The next
thing you notice is the size of the tank, which extends
down both sides, almost covering the engine and making
the bike look like a Paris-Dakar refugee. As it holds
three gallons and the bike does 140mpg at 55mph, its 400-mile
tank range means that crossing small desserts between
fill-ups is a distinct possibility! And as it’s
translucent, you don’t need a fuel gauge or a warning
light to tell you if you’re running low. Getting onto the bike
is the usual traillie clamber, but once you’re there,
the long-travel suspension compresses and the average
rider will have no problem getting both feet on the ground,
The saddle is narrow and fairly firm, but is not the razor-blade
affair that is often found on modern commercial off-road
machinery. After all, this is a bike that will be ridden
for some distances on tarmac surfaces, as well as on more
rugged terrain, so you wouldn’t want to have to
stand on the pegs all the time. In fact the riding position
is quite comfortable, helped by the narrow rear of the
fuel tank, which allows you to get a good grip on the
bike with your knees. Ahead of you, you’ve got the
usual cockpit instruments and lights that you’d
find on any Japanese motorbike – after all, the
running gear is almost straight Kawasaki, and as this
bike has to go on the roads as well, there’s the
usual complement of switches for indicators, lights, horn,
etc, in all the expected places. But it looks a little
bit more ruggedised than we’re used to seeing, and
you get the feeling straightaway that this a bike that
can take some harsh treatment, something that’s
reinforced by the substantial hand guards. Being diesel-powered,
the starting procedure is a little bit different from
normal, but thankfully you don’t have to kick it
into life, as it’s electric start. You simply switch
on the ignition, press the big red heater plug switch
for a couple of seconds, crack open the throttle slightly
and press the starter button on the right hand bar. The
single turns a couple of times before firing up, and then
settles into slow and steady thumping idle From
now on everything’s pretty much the same as any
single-cylinder traillie. The 5-speed gearbox is a standard
one-down, four-up pattern, so it’s into first, let
out the clutch and away we go. You immediately notice
that the diesel doesn’t pick up as quickly as a
petrol engine, and takes noticeably longer to get into
its stride. However it pulls cleanly with no hesitation
and pretty soon we’re running at a steady 70mph
along the roads around Shrivenham. Dropping down through
the gears to swing around the bends, there was less engine
braking than I was somehow expecting from a single-cylinder
diesel with its high compression ratio; it was somewhere
between a four-stroke and a two-stroke petrol engine.
When I mentioned this later to Dr McGuigan, he told me
that this is because diesel engines are not throttled.
This reduced braking meant that the engine also took longer
to slow down through the gearshifts, and if you let the
clutch out too quickly, the bike leapt forward quite dramatically.
Anyone watching would have thought I was doing my CBT!
However, it later turned out that there was a suspected
problem with the governor on the bike that I was riding,
which appeared to hold the throttle open. The second bike
at RMCS didn’t have this engine characteristic. The slower than usual
engine pick up meant that you also had to modify your
riding style slightly, opening the throttle earlier in
the corner in order to get the bike to drive through smoothly.
But at the same time, the torque delivery of the engine
meant that it would pull cleanly at any speed irrespective
of the gear that it was in. Opening the throttle to the
stop while doing 20mph in fifth didn’t faze it all,
and while the acceleration(?) didn’t fire you off
at lightspeed towards the distant horizons, the engine
didn’t bog down or get flustered at all. And for
a single-cylinder diesel, the vibration wasn’t too
bad at all. OK, it was obviously a single, and you could
certainly feel it through the bars, but it never really
intruded and I certainly felt that riding this bike for
hours on end wouldn’t cause any problems. With
a dry weight of 167kgs and the single front and rear disc
setup of the standard KLR650, braking performance is perfectly
adequate for the bike. Bear in mind that this bike will
be operating both on and off road, so feel and progression
is far more important than the initial bite of a road
bike setup.
The KLR650 is a well-mannered bike in its standard form,
and the fitting of the slightly heavier diesel engine
has not altered this. The bike remains sure-footed at
all times and you get plenty of feel from the dual-purpose
MT21s. It’s a very easy bike to ride, which is no
bad thing given the environment that it will be operating
in, and the variety of riders who’ll be using it.
In fact, once you get used to the engine characteristics
you can have a lot of fun. I would have loved to have
had the chance to take it off-road, but there wasn’t
the time or the facilities available to do this, and my
off-road skills are virtually zero. But I wouldn’t
have minded getting them sorted on this bike! So how does it
fare overall? Well, the first thing you have remember
is that this a machine constructed for a very specific
role and against a set of criteria that wouldn’t
apply to a normal bike manufacturer. So while this is
a bike that won’t set the world on fire (hopefully
it won’t have to be used to stop it going up in
flames!), it does work extremely well in the environment
it was designed for. The engine feels like it will go
on forever, the frame and cycle parts look as though they
could easily survive a parachute drop, and the whole package
inspires a feeling of confidence. Pre-production models
are currently on trial with the US Marine Corps and a
number of other NATO countries, and the initial feedback
is very good, and hopefully it won’t be too long
before this machine goes into full production. But
that’s not the end of it.
There’s considerable potential for this engine,
or a smaller variant of about 400cc, in bikes for third
world countries. It could also power all-terrain-vehicles
(ATVs) or pumps and generators in stationary applications,
where its ability to use “pink” diesel would
make good economics. So, the mixture of diesel and bikes
isn’t quite so bad as you first thought –
just so long as the fuel tank doesn’t leak!
And finally, if you’re thinking that you might like
to get your hands on one of these bikes, there is a possibility
that a civilian version could go into commercial production
sometime in the future. This is totally dependent upon
the military bike going into service, and then HDT will
be fully committed to supplying the military initially,
so there’d be no commercial sales for at least another
two years after that. So you can keep your cheque books
closed for the time being, and then get into the queue
behind me! My thanks to Dr
Stuart McGuigan and John Crocker of RMCS for their time,
and for giving me the opportunity to ride an extremely
interesting machine. |
Exploring diesel motorcycles and their unique features
Get yours here!
Diesel
and Bikes – Oh No !!
Feature article by
Dick Henneman
Ask any biker what things
they fear most when they’re out on two-wheels, and
one of the replies you’ll usually get is diesel.
So what if you carried three gallons of the stuff around
in your bike’s tank when you went off for a ride?
Wouldn’t it be like carrying the Grim Reaper as
pillion? Apparently not, if you have a military mind.
Let
me explain.
When
a modern country’s armed forces mobilises for action,
one of the biggest problems that the planners face is
logistics. In ordinary language this means getting all
the supplies, equipment, fuel, munitions, etc, to the
right place at the right time to support the troops and
their vehicles wherever they get sent. In the old days
this meant food for the horses and the troops, and what
couldn’t be carried in backpacks or in a train of
wagons, was foraged from the countryside. But as armies
became more mechanised the range of supplies that they
needed increased, and when the internal combustion engine
came on the scene, fuel and engine lubricants became essential
for progress. This meant that you either had to cart it
along with you, arrange for stocks to be strategically
placed along your line of advance, or have very good delivery
system set up. Let’s face it, you couldn’t
expect to drive your regiment or battalion onto the local
petrol station forecourt, flash the plastic, and fill
the tanks up! And if that wasn’t enough, you needed
diesel, petrol and aviation fuel to keep the whole thing
going. It was a logistical nightmare.
And it still is. But
the only vehicles that still need petrol are the military’s
fleet of motorcycles, so small but essential stocks of
this fuel still have to moved around in order to keep
the whole military machine purring along. Now just suppose
they had a bike that could run on diesel or aviation kerosene
. . . . ?
Ah,
now I begin to understand.
Enter stage left the Royal Military College of Science
(RMCS) in the UK and Hayes Diversified Technologies (HDT)
in the US, who between them were tasked to develop a bike
that would run on either of the two fuels that make up
99%+ of military fuel supplies. If this could be done
without reducing the bike’s performance, then they
would have a logistical winner. And if they could improve
some aspects of the bike’s performance, then it
would be a win-win.
Back
in 1993, the first steps were taken by RMCS to produce
a “feasibility demonstrator” based upon then
current diesel engine technology, to find out whether
this could be used as a low-risk development starting
point. This demonstrator bike used the crankcase and gearbox
from an Indian Enfield to keep costs down, and a rolling
chassis specially made by Eric Cheney. The results were
encouraging, and from this Dr. Stuart McGuigan and John
Crocker of RMCS went on to design a new engine, with development
and production being undertaken by Fred Hayes of HDT in
the USA. This machine used running gear from the Kawasaki
KLR650, a military variant of which was already in use
by the US Marines. The objective was to produce a high-torque,
high-revving normally aspirated unit so as to get the
most power from the size of engine, and the current version
delivers around 24bhp and 33ft lbs of torque from a 584cc
single cylinder unit that uses double overhead cams, four
valves and indirect injection. In the modified KLR650
frame, this gives a vehicle top speed of over 80mph and
a dry vehicle weight of 167kgs.
Anyway, enough of the
numbers and the technology – what’s it actually
like to ride! I went over to the RMCS at the invitation
of Dr. Stuart McGuigan to check out the bike and to see
what it’s like to go into battle on two-wheels.
At first glance it looks like any other big single
traillie, but without the vivid colour schemes and stickers
that we’ve become used to. In fact, in it’s
olive-grey drab paint its almost as though it’s
still in primer and they’ve forgotten to paint it.
But in a battlefield situation, you don’t really
want to go out of the way to attract too much attention
do you? I presume that the paint doesn’t absorb
radar pulses as well – but you never know! The next
thing you notice is the size of the tank, which extends
down both sides, almost covering the engine and making
the bike look like a Paris-Dakar refugee. As it holds
three gallons and the bike does 140mpg at 55mph, its 400-mile
tank range means that crossing small desserts between
fill-ups is a distinct possibility! And as it’s
translucent, you don’t need a fuel gauge or a warning
light to tell you if you’re running low.
Getting onto the bike
is the usual traillie clamber, but once you’re there,
the long-travel suspension compresses and the average
rider will have no problem getting both feet on the ground,
The saddle is narrow and fairly firm, but is not the razor-blade
affair that is often found on modern commercial off-road
machinery. After all, this is a bike that will be ridden
for some distances on tarmac surfaces, as well as on more
rugged terrain, so you wouldn’t want to have to
stand on the pegs all the time. In fact the riding position
is quite comfortable, helped by the narrow rear of the
fuel tank, which allows you to get a good grip on the
bike with your knees. Ahead of you, you’ve got the
usual cockpit instruments and lights that you’d
find on any Japanese motorbike – after all, the
running gear is almost straight Kawasaki, and as this
bike has to go on the roads as well, there’s the
usual complement of switches for indicators, lights, horn,
etc, in all the expected places. But it looks a little
bit more ruggedised than we’re used to seeing, and
you get the feeling straightaway that this a bike that
can take some harsh treatment, something that’s
reinforced by the substantial hand guards.
Being diesel-powered,
the starting procedure is a little bit different from
normal, but thankfully you don’t have to kick it
into life, as it’s electric start. You simply switch
on the ignition, press the big red heater plug switch
for a couple of seconds, crack open the throttle slightly
and press the starter button on the right hand bar. The
single turns a couple of times before firing up, and then
settles into slow and steady thumping idle
From
now on everything’s pretty much the same as any
single-cylinder traillie. The 5-speed gearbox is a standard
one-down, four-up pattern, so it’s into first, let
out the clutch and away we go. You immediately notice
that the diesel doesn’t pick up as quickly as a
petrol engine, and takes noticeably longer to get into
its stride. However it pulls cleanly with no hesitation
and pretty soon we’re running at a steady 70mph
along the roads around Shrivenham. Dropping down through
the gears to swing around the bends, there was less engine
braking than I was somehow expecting from a single-cylinder
diesel with its high compression ratio; it was somewhere
between a four-stroke and a two-stroke petrol engine.
When I mentioned this later to Dr McGuigan, he told me
that this is because diesel engines are not throttled.
This reduced braking meant that the engine also took longer
to slow down through the gearshifts, and if you let the
clutch out too quickly, the bike leapt forward quite dramatically.
Anyone watching would have thought I was doing my CBT!
However, it later turned out that there was a suspected
problem with the governor on the bike that I was riding,
which appeared to hold the throttle open. The second bike
at RMCS didn’t have this engine characteristic.
The slower than usual
engine pick up meant that you also had to modify your
riding style slightly, opening the throttle earlier in
the corner in order to get the bike to drive through smoothly.
But at the same time, the torque delivery of the engine
meant that it would pull cleanly at any speed irrespective
of the gear that it was in. Opening the throttle to the
stop while doing 20mph in fifth didn’t faze it all,
and while the acceleration(?) didn’t fire you off
at lightspeed towards the distant horizons, the engine
didn’t bog down or get flustered at all. And for
a single-cylinder diesel, the vibration wasn’t too
bad at all. OK, it was obviously a single, and you could
certainly feel it through the bars, but it never really
intruded and I certainly felt that riding this bike for
hours on end wouldn’t cause any problems.
With
a dry weight of 167kgs and the single front and rear disc
setup of the standard KLR650, braking performance is perfectly
adequate for the bike. Bear in mind that this bike will
be operating both on and off road, so feel and progression
is far more important than the initial bite of a road
bike setup.
The KLR650 is a well-mannered bike in its standard form,
and the fitting of the slightly heavier diesel engine
has not altered this. The bike remains sure-footed at
all times and you get plenty of feel from the dual-purpose
MT21s. It’s a very easy bike to ride, which is no
bad thing given the environment that it will be operating
in, and the variety of riders who’ll be using it.
In fact, once you get used to the engine characteristics
you can have a lot of fun. I would have loved to have
had the chance to take it off-road, but there wasn’t
the time or the facilities available to do this, and my
off-road skills are virtually zero. But I wouldn’t
have minded getting them sorted on this bike!
So how does it
fare overall? Well, the first thing you have remember
is that this a machine constructed for a very specific
role and against a set of criteria that wouldn’t
apply to a normal bike manufacturer. So while this is
a bike that won’t set the world on fire (hopefully
it won’t have to be used to stop it going up in
flames!), it does work extremely well in the environment
it was designed for. The engine feels like it will go
on forever, the frame and cycle parts look as though they
could easily survive a parachute drop, and the whole package
inspires a feeling of confidence. Pre-production models
are currently on trial with the US Marine Corps and a
number of other NATO countries, and the initial feedback
is very good, and hopefully it won’t be too long
before this machine goes into full production.
But
that’s not the end of it.
There’s considerable potential for this engine,
or a smaller variant of about 400cc, in bikes for third
world countries. It could also power all-terrain-vehicles
(ATVs) or pumps and generators in stationary applications,
where its ability to use “pink” diesel would
make good economics. So, the mixture of diesel and bikes
isn’t quite so bad as you first thought –
just so long as the fuel tank doesn’t leak!
And finally, if you’re thinking that you might like
to get your hands on one of these bikes, there is a possibility
that a civilian version could go into commercial production
sometime in the future. This is totally dependent upon
the military bike going into service, and then HDT will
be fully committed to supplying the military initially,
so there’d be no commercial sales for at least another
two years after that. So you can keep your cheque books
closed for the time being, and then get into the queue
behind me!
My thanks to Dr
Stuart McGuigan and John Crocker of RMCS for their time,
and for giving me the opportunity to ride an extremely
interesting machine.
Return
to Features Index Page