The original GSX-R750 was the
bike with which modern Japanese super-sports motorcycles were invented.
True, there had been plenty of last and fiery superbikes before the
oil-cooled four was unleashed in 1985. But the GSX-R750 was the first modern
race replica: a uniquely single-minded machine built for performance above
all else.
Its layout matched that of
Suzuki's endurance racers of the previous year, from the shape of the
twin-headlamp fairing to the use of 18-inch wheels (favoured by endurance
race teams because the larger diameter facilitated brake pad changes)
instead of the then fashionable 16-inchers. Its frame was made from
aluminium, instead of the steel used by rival superbikes. And its 749cc.
DOHC 16-valve engine was powerful, with a peak output of 100bhp @
10.50()rpm.
Oil cooling system
That output came from a motor
that used the novel (for bikes) system of oil-cooling to reduce cylinder
temperatures without the added bulk and weight of a water jacket. The Suzuki
Advanced Cooling System. SACS for short, allowed the engineers to redesign
the previous air-cooled GSX750 unit on a smaller, higher-revving scale.
Almost every component lost weight by being smaller or. in the case of the
cam cover, made from exotic magnesium instead of aluminium.
The GSX-R motor's output and
lightness were impressive, but it was the chassis that did most to give this
bike its unmatched power-to-weight ratio. At 3881b (176kg) the GSX-R was far
lighter than any rival 750. According to Suzuki, the new aluminium frame,
constructed from a combination of cast sections and extruded tubes, weighed
just I8lb (8kg). half as much as the GSX750"s less rigid steel item. Front
forks were stout 41 mm units, their rigidity boosted by an aluminium brace.
A racy instrument console, with
dials mounted in foam, hinted at the motor's liking for revs. Despite its
row of Mikuni flat-slide carburettors the Suzuki was quite rideable even at
low engine speed, feeling slightly buzzy without ever producing serious
vibration. But its delivery was flat until 7000rpm. when the bike suddenly
came alive, howling forward as the revs headed towards the 11000rpm limit.
High-revving performance
That high-revving performance,
allied to a slick six-speed gearbox and a top speed of 145mph (233km/h),
made the GSX-R a straight-line match for all its 750cc rivals. And in the
bends the Suzuki pressed home its advantage. Despite its 18-inch front wheel
the bike could be flicked into a turn with little effort, and was stable
once leant over. The GSX-R's lack of weight was a benefit in corners and
under braking, where it allowed the front brake - a combination of 300mm
discs and four-piston calipers - to deliver unprecedented stopping power and
feel.
But the GSX-R was one of the
first road bikes to require careful setting-up. and preferably a steering
damper, to handle well. The original model's occasional high-speed wobble
prompted Suzuki to introduce a slightly longer swingarm in 1986.
Practicality had barely been a consideration for the Suzuki's designers, but
the GSX-R750 did have a protective fairing and a strong pillion grab-rail,
to offset against its aggressive riding position, poor fuel range and narrow
mirrors.
Source of review: Fast Bikes by Roland Brown
The GSX-R750 was built to compete in the various worldwide championships
as well as to be used on the street. It is considered as one the very first
street-legal racers, there had been a number of sports machines but the
GSX-R750 was something else. It was a revolutionary motorcycle with
specifications like over 100 hp power output, less than 180 kg dry mass, 55°
leaning angle, lightweight alloy double-cradle perimeter frame, 18-inch
wheels and streamlined design based on the factory Formula 1 and Endurance
racers.
The air/oil-cooled motor had cylinder dimensions of 70,0 x 48,7 mm and had
29 mm flat slide carbs. In a racing trim (there was a tuning kit available
for competitive racing) the GSX-R750 engine provided 130 bhp. The new
high-tech engine was narrower than earlier inline-fours and materials like
magnesium was used to keep the weight down to minimum.
The GSX-R750 was basically a street-legal and detuned version of the works
GS1000R racer. The flat slide carburetors gave faster response to the
throttle compared to the vacuum carburetors. It also required the rider to
be more gently with the throttle. There were no compromises, it was very
quick in hands of a skillful rider but could be experienced as nervous and
even dangerous.
That is certainly the case in old and abused machines. The components of the
bike are all high quality but make sure that the tyres, suspension and
bearings are all in good condition or the bike can scare the living daylight
out of you! The GSX-R750 engine is considered as reliable but we all know
that there is no such thing as bulletproof engines. The frame of the early
models is not that rigid and bend easily when dropped.
The GSX-R750 entered the market in March 1985. There's not many bikes out
there in mint condition, most of them are ridden very hard and seen their
best days. Nevertheless the evolution of modern sports bikes started with
the GSX-R750. It's a real classic.
1985 Suzuki year code: F
With the 1983 RG250 Gamma, Suzuki was the first factory to deliver a true
racer replica using race-bred technology to the public. The next step was to
build a 4-stroke 400cc machine for the Japanese home market and a year later
a 750cc machine, culmination to the Suzuki's racing experiences in the World
Endurance, AMA Superbike and Championship. The GSX-R750 was first presented
at the 1984 IFMA Cologne Show in West Germany. Although it was fully street
legal, it was clear that it was built even to compete in the various
Worldwide Championships.
The GSX-R750F entered the market in March 1985. It was considered as the
first production motorcycle to offer race-bred technology and performance at
an affordable price. The design philosophy centered mainly on weight
reduction. Suzuki went counter to the conventional design by developing SACS
(Suzuki advanced cooling system) whereby the cylinder head and the pistons
are oil cooled via the engine oil injection, achieving cooling efficiency as
good as water-cooling without its weight increase. The computer designed
engine package was 10% lighter than the water-cooled versions.
The GSX-R750 also featured the new TSCC (twin swirl combustion chamber)
cylinder head, DAIS (direct air intake system , flat side carburetors,
six-speed gearbox and hydraulic clutch engaged the power. The chassis
featured the finest multi-rib extrusion molded aluminum box section piping
and cold-cast aluminum alloy components, MR-ALBOX frame, that weighted 8,1
kg less than half of the conventional steel frames. These and other weight
reduction measures gave the bike sensationally low dry weight of 179 kg, 20%
lower than the competing 750s, resulting a superior power-to-weight ratio
for much easier power control and quicker handling. Completing the GSX-R750
design was the endurance racer theme: dual headlights on the aerodynamics
full fairing and 18-inch tyres both front and rear.
As you can see from the pictures below (and the one above), there were
variations of the graphics and coloring. The one with the white lower part
of the fairing and black rear mirrors is a Japanese home market model, the
one with the blue rear mirrors in a USA model. The bike in the picture above
has black rear mirrors.
NOTE: Some of the photos on
Motorcycle Specs are owned by somebody. If you see any of your
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you object to it, I can remove it altogether. If any copyright
holder objects to their articles being placed on Motorcycle
Specs, it will be removed upon request. Any correction or more
info on these bikes will kindly beappreciated
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