We have tried to retain the looks of
the first V1000 model made over 18 years ago to maintain the classic appeal, but
if you look carefully you will notice modern radial tyres and uprated forks.
However, you will not see the computer engine management system, the new
internal oil system or the detail to the fit of parts identified over twenty
years of development.The sum of all this is a unique classic and modern machine
hand built just for you.
The Engine
The heart of the Hesketh's unique character is in its classical V-twin
engine. It's heritage stretches back to the turn of the century. Landmarks
created by such innovators as George Brough, and Phil Vincent, fed the
pre-eminence of the V-twin philosophy. Following Brough's withdrawal after the
war, Vincent carried the mantle of subsequent development, his Rapide, Black
Shadow and Black Lightning leaving an indelible impression even today,
thirty-five years after production ceased.
For a motorcycle, the 90-degree V-twin with transverse crankshaft has more to
commend it than any other engine configuration.
The relative simplicity
resulting from having but two cylinders extends to the ignition and
carburettors. Furthermore, the narrow configuration makes for a low centre of
gravity and low drag coefficient, the benefits of which are manifest in economy,
performance, balance and handling. Comparing a V-twins slim crankcase -little
wider than a single's - with that of a modern multi-cylinder indicates the
dramatic reduction in frontal area.
With a lower engine speed capability than the equivalent engine with more
cylinders, the V-twin produces greatly increased torque at lower engine speeds
allowing a more relaxed style of riding to achieve a given performance.
Despite slightly less even firing intervals than are given by a narrower
cylinder angle, the 90 degree V-twin is fundamentally the better as its
crankshaft can be counterweighted to give perfect primary balance. Installed as
in the Hesketh, with the front cylinder almost horizontal, it has proved to be
very smooth together with first class cooling characteristics and eliminating
undesirable gyroscopic or torque reaction effects.
The basic philosophy of the Hesketh
as an enthusiast's performance touring machine has dictated the criteria in
terms of engine characteristics and performance. The decision to adopt a V-twin
configuration was followed by years of concentrated research, design.
development and testing, blending a traditional engine concept with the finest,
and in some cases innovative features of modern technology.
The production engine is a well oversquare 992cc V-twin. An extremely high
design strength was the fundamental requirement in the conceptual stages,
illustrated by the very robust bottom half, the castings of which embody the
gearbox. Following the rigidity theme, the crankcase mouths are extended to
embrace much of the cylinder liners, with the result that the aluminium jackets
of the barrels are very short.
The Hesketh engine features a one
piece steel forging , exceptionally stiff, running in large diameter roller
bearings; Aircraft specification steel blanks are used for the connecting rods
which have split big ends housing copper-lead bearings of high load carrying
capacity.
In order to achieve the designed performance and efficiency, with excellent
breathing and precise valve control at the higher end of the engine speed range,
the adoption of DOHC four valves per cylinder heads was considered essential.
The valves have an inclined angle of 40 degrees in aluminium casting with flat
top pistons giving highly efficient pent roof combustion chambers and a
compression ratio of 10 to 1. Roller chains, with slipper type tensioners and
anti flutter strips, drive the camshafts which are supported in needle roller
bearings and actuate the valves through inverted bucket tappets.
The ignition used is a high
efficiency electronic computer control system for consistent timing at all
engine speeds on both cylinders and freedom of maintenance. The fuel mixture is
provided by two Dellorto carburettors with accelerator pumps and paper element
filters and the lubrication system (again with a paper element filter) embodies
a positive feed to the crankshaft, cams and gearbox are feed from a secondary
system - a feature contributing significantly to the Hesketh's longevity. Engine
starting is electric. The combination of a triple reduction drive and heavy duty
battery supplying ample power at all times.
The Transmission
The two helical gears of the primary drive are wide and durable and their
centres optimised for quiet running. Incorporated in the output gear is a
multiplate wet clutch more than adequate for the engine's high torque
characteristics. The clutch is of conventional design but its actuation is by a
hydraulic system to ensure ultra smooth action with automatic adjustment and
high mechanical efficiency.
The high torque characteristics result in the Hesketh requiring only five gears
to achieve its full speed range. The compact gear cluster is of traditional
British design. Gears and the very rigid shafts all run in Torrington low
friction needle roller bearings. A noteworthy and innovative facet of the
transmission is the train of gears between the gearbox output and the shaft
carrying the final drive sprocket.
This layout enables the sprocket to be
coaxial with the pivot of the rear suspension fork. Since the usual variations
in chain tension with the wheel travel are thus eliminated, the 5/8 in pitch
sealed rear chain has extremely good wear characteristics and when adjustment is
required is quick and simple being controlled by keyed eccentric bushes in the
rear fork, eliminating the need for the heavier and more expensive shaft drive
system.
The Frame
The frame is a light but rigid Sifbronze welded duplex structure with the
engine/gearbox forming the lower half and acting as a stressed member. The
material used for the construction is Reynolds 531 tubing (recognised as being
unsurpassed for this purpose) with thorough triangulation at the steering head
for the necessary torsional stiffness essential to good handling
characteristics.
The standard frame is finished in
stove enamel to a colour of the customers choice.
The 43mm telescopic front forks, renowned for rigidity, excellent damping and
long service life, have been chosen for the front suspension whilst the rear end
stiffness is helped by unusually wide spacing of the fork's pivot bearing which,
being Timken taper roller units, are extremely durable. The Marzocchi rear
spring damper legs have multi rate springs with preload adjustment together with
gas progressive stage damping.
The hydraulically operated disc brake assemblies have twin 310mm discs at the
front and single 270mm disc at the rear giving extremely powerful and fade free
braking; interaction between the rear brake and suspension is precluded by a
parallelogram linkage from the rear of the gearbox to the floating aluminium
torque arm carrying the calliper, allowing the suspension to work at optimum
efficiency, even under hard braking conditions.
Close attention to practicality and riding comfort has resulted in a fuel tank
sufficient to hold 22 Litres
yet slim enough for good knee grip. High engine
efficiency has resulted in a cruising range from a full tank of over 200 miles.
The overall styling, including the tank, seat and rear fairing, headlamp cowl
and enclosure panels was designed in consultation with John Mockett who has
become established as Britain's top motorcycle stylist.
The Hesketh is well equipped.
Electric's include a Lucas RM24 15-amp alternator and a Bosch H4 halogen
headlamp for excellent range and lateral spread; the 12-volt 27Ah battery and a
compartment housing a total of 5 fuses are situated between the side panels
behind the rear cylinder. In addition to the obligatory speedometer with
mileometer and trip meter, the instrument panel carries a tachometer, warning
lights for key functions and a quartz clock, while self cancelling turn
indicators and mirrors are standard.
Any corrections or more information on these motorcycles will be kindly appreciated.