Additional photos of this 1991 Suzuki GSX-R750 are available here for your perusal.
In 1982, Suzuki began development of what would become a total game-changer of a sportbike and the first bonafide Japanese race-replica. Dubbed the GSX-R750, the new road-legal track weapon was unlike anything that had come before it. It was crazy lightweight, brimming with componentry previously only seen on race machines, fast as hell, and sold at a shockingly affordable price.
Suzuki was looking to develop a winning four-stroke model, and as per usual turned to its race program for the answers. Using lessons learned from experience in TT-F1 and Endurance efforts, the blueprints for a new 750 began to emerge. For the frame, Suzuki designed a trick aluminum-alloy double-cradle perimeter frame derived from the RG250 Gamma’s chassis.
Narrow and rigid, the new frame weighed 20 lbs less than the conventional steel units of the day. Equally track-oriented was the GSX-R’s 41mm forks, mono-shock, triple 300mm drilled discs, and 18-inch wheels.
The Gixxer’s engine was another major highlight, having taken lessons from the Suzuka-winning GS1000R (aka XR69) works racer. The 747cc, 16V, DOHC, inline-four featured flat slide carbs, Suzuki’s new TSCC (Twin-Swirl Combustion Chamber) cylinder head, DAIS (Direct Air Intake System), and magnesium rocker covers.
One major area that set the 750 apart and allowed it to be so lightweight was its cooling system. Designed by Suzuki engineer, Etsuo Yokouchi and known as SACS (Suzuki Advanced Cooling System), the setup used the engine’s oil injection to cool the cylinder head and pistons and air to cool the cylinders. SACS could achieve the efficiency of a water-cooled system without the considerable weight.
Weighing in at just 388 lbs, the GSX-R750 was around 70 lbs lighter than its three-quarter-liter competitors like Yamaha’s FZ750 and Kawasaki’s Ninja 750. With the power of a liter-bike that tipped the scales at less than your average 600, the Gixxer was incredibly nimble and flickable, with its 5.5-inch ground clearance and narrow construction affording a cool 55-degrees of lean angle.
On top of its stellar performance, the ‘Zook also looked the business. Its bodywork was incredibly aerodynamic, having taken inspiration from the company’s factory endurance machines, with its twin headlights, four-into-one race exhaust, and boxy tail section. Even the livery stems from Suzuki endurance racers of the era.
Suzuki pulled the cover off the first-year GSX-R750 (model code: F) at the 1984 Cologne Motor Show, before its official launch in March of 1985. Upon its release, the Gixxer was unquestionably king, setting a new benchmark in the industry. And unsurprisingly, it didn’t take long for the GSX-R to start winning on the race track. The new model won the 1985 TT with rider Mick Grant, while a young Kevin Schwantz straight up dominated the Transatlantic series.
In the subsequent years, the mighty Gixxer saw a number of revisions before 1990, when the three-quarter-liter beast was given a major model update. That year, Suzuki bestowed the GSX-R750 with a host of features borrowed from the race-spec double-R model (GSX-R750R), including its long-stroke engine layout, lighter pistons, new Mikuni model BST38SS “Slingshot” carbs, upgraded connecting rods and cylinder head, smaller valves, a revised stainless four-into-two-into-one exhaust culminating in a single muffler mounted on the right side, and new suspension that yielded increased adjustability.
The chassis also underwent revisions at the start of the decade, utilizing some elements form the 1989 GSX-R1100 with a 25.5-degree rake and a 55.7-inch wheelbase. A wider rear tire (which were now Michelin radials), up to 5.5-inches from the outgoing model’s 4.4-inch item and a steering damper was also added to the mix. 1990 also marked the first year that the illustrious Gixxer was fitted with a (41mm) inverted fork.
The next year in 1991, the ‘Zook was given its first significant visual makeover, getting a new tail section, less rectangular-shaped side vents in the bodywork, and a new front fender was introduced to better accommodate the inverted front-end (though that last featured didn’t extend to US models).
The biggest change for ’91 was undeniably its new front fairing design. Gone were the original Suzuka-style double headlight arrangement, and in its place was a slanted nose fairing that hid headlights several inches behind a clear headlight cover, giving the bike a more aggressive and contemporary appearance while also bolstering aerodynamics. On top of also getting a new, larger seat, ’91 marked the final year of the oil-cooled SACS-engined version of the Gixxer.
Running gear on the ’91 750 was comprised of a 41mm USD fork, adjustable for preload, eight-way damping, and ten-way compression, while in the rear the bike got a full-floater mono shock with remote reservoir and four-way adjustable preload and rebound damping. A pair of 310mm discs — which were revised for 1990 — bit by four-pot calipers provided stopping power (aided by a single 280mm disc and one-piston caliper in the rear). The swing-arm was changed to a 45mm box tube section cast unit, while the wheels were 17-inch three-arm alloy items.
Powering the 1991 Gixxer 750 was an air/oil-cooled, 749cc, 16V, DOHC, inline-four, married to a six-speed constant mesh transmission. All the changes resulted in an output of 116 hp at 11,000rpm and 57.5ft-lbs of torque at 10,000rpm, which translated to top speed exceeding 150 mph, and the ability to fire off standing quarter mile sprints in under 11-seconds — despite its approximately 550 lb wet weight.
Today, we’re offering a well-kept 1991 Suzuki GSX-R750 (VIN: JS1GR7AA2M2100237) with just shy of 20,000 original miles that, aside from a Vance & Hines muffler, is entirely stock. The gauges have been replaced and the tachometer does not work, but this specimen is otherwise in good shape. Cosmetically, this example is in great condition for a nearly three-decade-old machine, though upon close inspection there are a few minor cracks and flaws. There is also a bit of pitting and oxidization on some of the exposed metal.
It was recently given a ~$2,600 service by HyperCycle so it’s turnkey, though the polished frame is definitely not stock. As Adam puts it, frame polishing was so popular at the time that we’d almost call it “period correct”!
The 1991 GSX-R750 marked an interesting transitional point in the evolution of the legendary motorcycle. It still featured much of the same tech and engineering that made the inaugural Gixxer 750 such a smashing success, while boasting the first heavily revised bodywork that would ultimately segue into the unapologetically ‘90s versions that came after.