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Sherco
3.2 4T, a new time but the goals are the same
Sherco
launches its new 4T Trial bike using the same mentality that
has resulted in the very successful 2T predecessors
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Because of the FIM
changes in the current regulations which promoted the
participation of bikes equipped with four-stroke engines in
the World Trial Championship in the near future, Sherco started
to develop a new bike that will surely become the future of
the Trial specialty.
Sherco has repeatedly shown a taste for challenges, and this
was a really exciting one. This is the reason why, unlike others,
Sherco stopped chasing victories at any cost two years ago,
concentrating instead on the task of designing and developing
a new 4T engine capable of convincing even the most skeptical.
Sherco has also tried to avoid any kind of inferiority complex
when comparing the 4T with the 2T. The 2T bikes will still be
available, due to market demand, while regulations still allow
this situation. Moreover, the 2T 2005 Trial model lineup has
been completely and thoroughly renovated and have passed the
Euro2 official approval, the current 2T models are approved
until the year 2008.
However, Sherco is convinced that the 4T engines will be dominating
the sport in the near future, and our main objective is to become
the front-running firm when the 4T engines start their reign.
Today, Sherco using our proprietary designed engine and
chassis owns the most compact, reliable and efficient
2T bike in the market, and it would be a shame to waste all
the effort behind it. This is why the main goal of the Sherco
Trial 4T designing team led by Josep Rovira Paxau
has been very careful to ensure that the 4T mechanism is perfectly
adapted to the existing cycle part. As everyone can see, this
goal has been fully achieved. |
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What has been the key to this success? Undoubtedly, the fact that the
designing process started from scratch. Just like we did when we entered
the trial category, and when we designed our enduro bike unlike
other trademarks -, we did not simply resort to adapting an already existing
mechanical base. Instead, we worked with the idea that to obtain maximum
efficiency we needed to design an entirely new engine. Designing each
component specifically for trial has always been the best way to create
an engine which is, at the same time, perfectly apt for trial practice,
and perfectly adaptable to a cycle part which has proven its efficiency
throughout several years. The new Sherco Trial 4T engine is as compact
and light on the outside as it is efficient and reliable on the inside!
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The results that Josep Rovira Paxau wanted to obtain were the same goals
he has always pursued: mechanical simplicity and maximum efficiency. Right
now, there is no other reference in four-stroke trial mechanics. Therefore,
trying to use an already existing mechanical base was out of the question.
The only premise which guided the whole process towards finding
the ideal formula was that the new 4T engine had to be, at least,
as powerful as the two-stroke Sherco 2.9 (272 cc). After testing different
combinations of material, systems and components, the final internal measures
were decided: 82mm-diameter bore and a 60mm-stroke; that is to say, a
super-square engine with a short stroke and 317cc. A lower cylinder capacity
would make a four-stroke engine much worse than a two-stroke engine, especially
regarding its dynamic qualities. This high cylinder capacity provides
a powerful engine, while the four valves ensure excellent ventilation
and, at the same time, a high rpm potential (if needed). The cooling system
is liquid-powered, the timing gears are driven by a Morse chain controlled
camshaft (maximum reliability) and a VHST 28mm DellOrto carburetor
takes care of the intake system. Despite the knowledge about electronic
injection that Sherco has acquired thanks to the Enduro 4.5i -,
the lack of similar systems in the trial category advised against its
use. After all, using a conventional carburetion system ensured that there
would be no problems at all and it would put the minds of the customers
at ease. Finally, after working together with Leonelli to design a programmable
digital ignition system, the usual retention problems with four-stroke
engines have become a thing of the past at least, thats the
case with the Sherco Trial 4T. With this bike, trial can be practiced
inside a range of 1,400rpm and 2,500rpm, thanks to the incredible response
of the engine, which provide outstanding traction capabilities. And if
the road we are riding needs an rpm increase, the Sherco Trial 4T provides
it easily and quickly, thanks to the four valves and to the lightness
of the engine components.
As we have already stated, one of the keys to success of this bike is
having taken full advantage of the cycle part from its two-stroke counterparts.
This is a good proof of its compactness and lightness. This way, the frame
is a perimeter-type double loop with a rectangular-section steel tube,
and an aluminum swingarm. The main difference resides in the front braces
of the frame, which are now detachable, and make the engine easily accessible.
The front suspension is controlled by a conventional 38mm Paioli fork.
The rear is controlled by a progressive system with links that act on
a Boge rear shock absorber. Both wheels are equipped with disk-brakes.
As a result, the new Sherco Trial 4T is practically identical to its Sherco
2T counterparts regarding size and dynamical performance, and its weight
is only increased by a few kilograms, thanks to carefully selected materials
and to individually designed engine parts. Broadly speaking, the 4T weighs
just 2 kg more than the 2T but, considering the fact that the new exhaust
pipe weighs 1 kg less, the new Sherco 3.2 4T is still lighter than most
of the rival 2T bikes in the market.
As difficult as it seemed, Sherco has done it!
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Engine
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4 stroke SOHC, 4 valve Sherco proprietary technology
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Capacity
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317
cc
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Bore x Stroke
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82
x 60 mm
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Cylinder lubrication
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Unleaded gasoline. Nikasil coated cylinder treatment
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Cooling system
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Closed water circuit with constant water circulation.
Electronic thermostatically controlled fan.
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Start
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Geared system with foldable pedal
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Carburettor
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Dellorto VHST 28 mm
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Exhaust
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Steel pipe with single aluminium muffler integrated
in the body
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Transmission
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5 speed sequential gearbox with security selector system
to prevent no-gear insertion. Gears in primary
drive, secondary drive with
chain
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Clutch
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Hydraulic, multidisc in oil bath
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Ignition
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Leonelli digital programmable ignition and balanced
magnetic flywheel
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Skid Plate
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Made
of stamped Ergal
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Chasis
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Deltabox type made in Chrome-molybdenum. Chromed finish
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Petrol tank
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Made in nylon. Capacity 2,8 l.
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Brakes
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Hydraulic AJP, floating 185 mm Ĝ in front and 145 mm
Ĝ in rear
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Front suspensión
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Hydraulic telescopic fork Paioli 38 Ĝ. Travel 170 mm
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Rear suspensión
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Progressive link system with single Boge absorber. Travel: 175mm
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Front Wheel
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Morad
21" aluminium rim and aluminium hub, steel spokes. Michelin tube-type tyre.
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Rear Wheel
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Morad
18" Aluminium rim, hub with secondary transmission chain wheel,
steel spokes. Michelin
tubeless tyre
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Weight
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73
kg.
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Wheelbase
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1,332mm
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Ground clearance
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305
mm
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Seat height
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635
mm
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