Under the Radar
Suzuki GS1100 E/ES
Years produced: 1980-1983
Claimed power: 108hp @ 8,500rpm (1983)
Top speed: 140mph (1983 test)
Engine type: 1,074cc air-cooled DOHC 16-valve inline four
Weight: 552lb (w/half-tank fuel)
Price then/now: $4,350 (1983)/$2,000-$4,000
It’s fair to say that the basic design criteria for today’s four-pot, racer-on-the-road sportbikes were established in the early 1980s: Kawasaki introduced fuel injection on its GPz bikes (Kawasaki GPz550, Kawasaki GPz750); Honda gave us liquid cooling in the VF range (1984-85 Honda Sabre VF700S, 1985 Honda VF1000R); Yamaha pioneered a peripheral frame in the Yamaha FJ1100; and Honda was also first to fit 16 valves on a four-banger with the Honda CB750F. But after trailing the pack as the last of the Big Four to abandon two-stroke technology, Suzuki leapt to the front with its 1977 Suzuki GS750 and Suzuki GS1000. In 1980, they moved the bar higher still with the Suzuki GS1100.
The GS1100E can truly be called the first “modern superbike” because of its use of a four-valve cylinder head with a narrow included valve angle and wedge-shaped squish band combustion chambers — technology first used by Cosworth in its race car engines. Suzuki called its version TSCC, or “Twin Swirl Combustion Chamber.” It made the GS1100E the fastest bike on the strip when introduced in 1980, and good enough to be named Cycle World’s Superbike of the Year for three consecutive years from 1981-1983.
Though based on the earlier two-valve GS range, the E used a new cylinder head with double overhead cams and shared cam lobes, each lobe opening two valves via forked cam followers. Screw and locknut adjusters made clearance setting easy, unlike the shim-and-bucket setup found on most DOHC bikes of the era. The engine’s bottom end used the built-up crank/roller bearing design of the two-valve GS850 and 1100 (a leftover from Suzuki’s two-stroke days) which, though more costly to produce, gave benefits in reduced friction losses and added strength and durability. Fueling came by four 34mm Mikuni CVs, with the gas ignited by a transistorized electronic ignition. Drive to the five-speed transmission was by a helical gear primary, and chain to the rear wheel.
Though conventional in using steel tube cradle construction, the GS1100E frame was stronger and stiffer than most, and the box-section aluminum swingarm added to the steering rigidity. The air-assisted KYB front forks featured adjustable compression and rebound damping, and for 1982 the GSE gained fashionable anti-dive forks (Cycle World called them “largely ornamental”) by Showa. These used pressure from the front brake’s hydraulic system to close damping valves, limiting fork movement. Blow-off valves allowed for sharp road shocks. Time has passed judgment on the usefulness of such accessories, but they were all the rage in 1982. Brakes were triple discs with floating calipers.
The GS1100E consistently won period shoot-outs against the 1,047cc six-cylinder Honda CBX and Kawasaki’s GPz1100. Then for 1983, Suzuki upped the ante by increasing intake valve lift and advance while revising intake and exhaust systems for an extra three horses. Forged pistons, a stronger crank and uprated transmission components maintained the GS’ reputation for reliability; a frame-mounted bikini fairing provided improved aerodynamics. The 1983 GS1100ES was the first production motorcycle tested by Cycle World to run a standing quarter mile in the tens. This was serious stuff.
“Not the most powerful motorcycle on the market nor the fastest. What it is is the quickest,” wrote Cycle World in September 1983. The Honda CB1100F made the same power but was heavier; the GPz made more power but had a narrower power band and a grabby clutch; and the Suzuki Katana with an identical engine was lighter and more aerodynamic, but more difficult to launch. The other contender, Honda’s V65, was heavier and exhibited quirky handling. Overall, the shoot-out awards went to the GS1100ES.
The GS1100ES’ combination of consistent sub-11-second quarters, nimble yet stable handling, long-distance touring comfort, simple maintenance and bulletproof reliability contributed to the GS1100E’s position as fifth “most significant motorcycle” from the previous 35 years by Rider magazine in 1999.
The conclusion reached by motorcycle journalists in 1983 was that the GS1100ES was simply the best all-round big bike on the market. Perhaps Cycle World said it best: “The engine and frame and suspension are right. The motor is brilliant, making tons of power at every engine speed without ever seeming to work at it. The GS … doesn’t overpower its chassis … the suspension is excellent under most conditions. Taken as a whole, as a complete motorcycle, the GS works, and works well.”
1983 Kawasaki GPz1100
• 104hp @ 8,500rpm (1983)/149mph (period test)
• 1,089cc air-cooled DOHC 8-valve inline four
• Disc brakes front and rear
• 578lb (wet)
• Price now: $2,500-$4,500
The Kawasaki GPz1100 was the GS1100 E/ES’ most obvious competition. Though using only two valves per cylinder and essentially derived from the legendary 1973 Kawasaki Z1, Kawasaki gave it fuel injection for added pizzazz — with analog control in 1981, and fully digital with a throttle position sensor in 1982. Changes to cam timing and lift that year were claimed to boost power above 110hp at the crank, and while the Kawasaki developed more peak power than the GS, the Suzuki smoked it in the lower rev range.
The engine was rubber mounted in the frame and drove the five-speed tranny by straight-cut gears. The “DFI” digital fuel injection wasn’t perfect, though, found Cycle World, as the engine would sometimes die when the throttle was opened abruptly; their testers also experienced power surging at cruise. While FI systems are now very reliable, back in the day, Cycle World was concerned that if it failed, it was something few could “tackle at the roadside.”
Spring rates and suspension calibration changes for 1982 gave the GPz a handling advantage over the GS, with better track manners, lighter steering and more ground clearance, though the GS scored higher in comfort and stability. The big change came in 1983 with Kawasaki’s Uni-track rear suspension. And that, as they say, changed everything …
1983 Honda CB1100F
• 108hp @ 8,500rpm (claimed)/144mph (period test)
• 1,062cc air-cooled DOHC 16-valve inline four
• Disc brakes front and rear
• 580lb (wet)
• Price now: $2,000-$4,000
Every motorcycle niche includes a Honda, and Honda’s head-to-head competition with the 1983 GS1100ES was the CB1100F, the ultimate development of the CB750 Four of 1969. Although something of a stop-gap model while the VF1000F Interceptor was being readied for 1984, the CB1100F nevertheless boasted an impressive specification.
Incorporating technology from the Euro market CB1100R and Honda CB900F, the four-valve engine produced a claimed 108hp at the crank, and was packaged in a conventional steel tube frame with a bikini fairing, TRAC anti-dive forks, cast alloy tubeless-tire wheels and adjustable handlebars. The result was a good looking bike that not only equaled the GS and GPz in performance (top speed was better than the GS, although the GS would beat it in the all important quarter mile), but was also less expensive, coming in at $3,698 against $4,499 for the GPz and $4,350 for the GS1100ES in 1983.
The CB900F that came before the 1100 had a reputation for missing gears and also had some handling issues, both of which were corrected in the 1100. The engine was fully rubber mounted to quell buzzing. The result was a powerful, competent and comfortable mile-muncher that held up Honda’s reputation during the troubled early days of the V-4s. MC
Read more about the motorcycles mentioned in this article:
• Kawasaki GPz550
• 1982 Kawasaki GPz750
• 1984-85 Honda Sabre VF700S
• 1985 Honda VF1000R
• 1984 Yamaha FJ1100
• Honda CB750F: A Classic for the Masses
• 1977 Suzuki GS750
• 1978 Suzuki GS1000
• 1981 Honda CBX
• 1983 Honda CB1100F
• 1982 Suzuki Katana GS1000SZ
• 1973 Kawasaki Z1: The King of the Road
• 1981 Honda CB1100F