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Issue link: https://magazine.cyclenews.com/i/146687
(Left) The single-sided front suspension system was designed
by RAnD's James Parker. The GTSlOOO is the first massproduced motorcycle to feature such a design. (Below) The
Omega chassis is constructed of multiple aluminum castings
and is claimed to provide a lower center of gravity.
systems bolting directly to its sears.
The new frame design is a raaical
departure from the conventional
"backbone" design, and is claimed to
be significantly more rigid.
A backbone frame - along with
conventional front fork suspension transfers braking and suspension
forces up the fork, through the frame
and down to the rear suspension.
However, the Omega frame design,
coupled with the single-sided front
swingarm .suspension, transfers those
forces in a straighter line, resulting in
a more rigid design. Perhaps the
biggest advantage of the new design
is the absence of front-end dive whilebraking.
The front suspension system,
invented by James .Parker of
Rationally Advanced Design Development Inc. (RADD), allows the machine
to enjoy independent steering and
suspension functions while providing
exceptional rigidity while braking.
The front swingarm pivots are-widely
placed to spread side and torsional
stress over a wide area, and the system
provides 4.57 inches of wheel travel
while offering rebound and compression adjustment.
Rear suspension duties are handled
by a more-traditional double-sided
Deltabox rear swingarm and a coil
spring/oil damper shock. The risingrate linkage-type system features
adjustable rebound, damping and
preload and boasts 5.12 inches of rear
wheel travel.
Steering is achieved with a handlebar crown that transmits input
through a steering box to a vertical
spar that turns the front wheel. The
vertical spar is supported by an upper
arm that is mounted between the top
of the spar and the main frame, and
the steering head is supported by a
subframe that is also attached to the
main fr~me.
Inside the off-set front wheel is a
330mm front disc that is centrally
located and mated to an opposed sixpiston brake caliper. Both the front
and rear brakes are connected to an
electronic anti-lock control unit.
Powering the motorcycle is a lOO3cc,
liquid-cooled, slant-block double overhead cam, 20-valve, four-cylinder
engine, based on the same powerplant
that powers the FZRlOOO sportbike. The
motor is slanted forward in the frame
to lower the overall center of gravity.
Electronic fuel injection provides
consistent power through a myriad of
sensors that monitor each cylinder and
control the fuel/air ratio. A catalytic
converter contained within the exhaust
system reduces exhaust emissions.
In -.its first year, the GTSlOOOA will
be available in ~quantities.
Yamaha has yet to determine how many
units will be produced, and will base
their decision on dealers' response.
- - - - - - Continued on page 25
From adream to reality
hile the Yamaha GTSlOOA is the
lint mass-podua.d IDOtOI'Cyde 10
feature a single-sided front swingarm suspension system, the conttpt
itself bas been fIoa1ing around in the
mind of its inventor, James Parker, for
over 14 years.
Parker, pm.ident of. Santa Fe. New
Mexico-based Rationally Advanced
Design Development Incorporated
(RAnD), began 10 develop his invention
in the late 1970s. At the time, a number
of European inventors were toying with
but few were
able '10 Q9a<:oJUe ~
prac:tical difficulties thai: arose. In 19'18,
W
Parker began to attack the problemhimself, and in 1982 compIeud the final
pieces of his COIlC':q)L
Parker approached Honda with his
designs, but Honda engineers had
difficulty grasping the concept from the
drawings. Parker then set out to hand
build the fiISt prototype, and proc:1uald
his front-end suspension system on a
Honda XL600 dual sport motorcycle.
After a oomplete teehnkal evaluation
of the prototype, Honda declined
Parker's proposal to help the company
prodUce such a motorcycle.
In 1984, Parleer approached other
manufacturers with bis ideas. A spark
.
U\$Ulll:(i in a test
session with
I3O!J:
who ~ impressed with the handling
of the prototype H