Retrospective: Suzuki GS1150E: 1985 – 1986

story and photography by Clement Salvadori

[This Retrospective: Suzuki GS1150E: 1985 – 1986 was originally published in the May 2011 issue of Rider magazine]

Talk about naked power! This baby had it, an unfaired motorcycle with more than 100 horses at the rear wheel. Nothing delicate about this model. As the 1985 ad read: “Four-stroke, 16-valve DOHC four-cylinder engine with Twin Swirl Combustion Chambers (TSCC). Full Floater rear suspension with remote hydraulic preload adjustment. Posi-Damp fork with anti-dive. Triple disc brakes.”

Brute power, in a chassis that handled OK; not great, but OK. The box-section, full-cradle frame held the motor tightly, with the fork providing almost 6 inches of travel, the single shock absorber 4.5 inches. The rising-rate “Full Floater” aspect of the Kayaba shock extended the wheelbase to 61 inches, 1.6 inches longer than on the previous GS1100E. With the gas tank half full the weight was a hefty 550 pounds, but if the rider kept the rear wheel under control at the drag strip, it could turn the quarter-mile in less than 11 seconds and more than 120 mph. Top speed was said to be somewhere on the far side of 140 mph.

This was seen as the last of the breed of big “standards,” unfaired motorcycles, powered by air-cooled, in-line four-cylinder engines. It had begun with Honda’s CB750 in 1969, then Kawasaki’s 900 Z1 in 1973. Suzuki was really the fourth of the Big Four to get on the four-stroke bandwagon, staying with excellent two-strokes, like the X-6 Hustler in the ’60s, the GT750 Le Mans triple in the ’70s, until the GS750 came along in 1977. I’ll be kind and not mention the RE5 Wankel rotary.

The GS750 had a great eight-valve DOHC engine, and one of the better chassis available at the time. This was soon followed by the GS1000 in 1978. Then the ante was upped with the 16-valve GS1100 in 1980—and that “Twin Swirl” concept. The GS1000 combustion chambers were more or less smooth and hemispherical in shape, but when the company doubled the number of valves, a lot of time was spent at the drawing board, figuring what to do to ensure the most complete combustion. Research showed that if the mixture were agitated properly, it would combust better, so little angles were built in to rough up the flow. With the TSCC in place Suzuki claimed a 20 percent increase in combustion efficiency.

To appeal to home mechanics, the 16 valve gaps were adjusted with screws and locknuts, not the time-consuming work involved in replacing shims—always a problem when the right shim was not in the box.

In the early ’80s Suzuki had be­- gun working on its next project, the fully faired, pseudo-racer GSX-R series, but the marketeers felt that one more go-round with the GS would work. It wouldn’t cost much to bore out the cylinders a couple of millimeters, from 1,074cc to 1,135cc, put on larger constant-velocity Mikuni carbs, 36mm to replace the 34s on the 1100, bigger intake valves to allow more fuel to pass through, new camshafts, a slightly raised compression ratio, 9.7 vs. 9.5, and Bingo!…10 more ponies. The engineers all deserved a bonus for that inexpensive redesign.

It was the chassis that brought out the genuinely new thinking, and most likely the backroom boys wanted to test some ideas that they were going to use on the GSX-R models. Instead of that round tubing, the frame was constructed out of box-section aluminum, as was the swingarm, and the engine was held higher. Nothing touched in the corners except the folding footpegs, although an aggressive rider could find the stock Bridgestones a tad liable to slip in the corners when in knee-scraping mode.

The 37mm Kayaba fork had a rake of 28 degrees and, on the stock 1150, ended in a 16-inch wheel; this 16-inch front-tire size was fast becoming a highly debated subject, especially after it appeared on Kawasaki’s 1985 Ninja 600. Somewhere along the line, this particular 1150 in the photos got refitted with a 19-inch wheel, though the current owner has no idea who did it, or why…but he has no complaints about the handling. Another change is that a 4-into-1 Vance & Hines exhaust has been fitted.

Decent brakes meant that dual-piston calipers squeezed down on the three discs. This was the short-lived (thankfully) era of anti-dive contraptions, and the 1150 had Suzuki’s Positive Damping Force (PDF) system in play; its biggest problem was that the two units had a hard time discerning between hitting a bump and applying the brakes. With four adjustments possible, the knowledgeable rider usually left it at number 1, the least intrusive.

Suzuki was looking hard at the competition and when the designers saw Kawasaki’s GPz1100, Honda’s Euro-only CB1100R, and Yamaha’s FJ1100, they felt that fairings on sport motor­cycles were the “in” thing, bringing the bike into the café-racer category. As a result, the factory deemed that a half-fairing would be a necessity on this street model. And the first 1150 to run down American roads in 1984 was the GS1150ES—with low handlebars which were not terribly well received.

A little too much vibration reached the rider, too; nobody quite knew why, though one opinion was that the fairing itself was part of that buzziness problem, its large frontal area creating a surface that enhanced the vibration.

For the 1985 model year Suzuki came out with the standard version we are looking at here. Leaving the fairing off was a minor weight saving of 8 pounds, a financial saving of about $400—the 1985 GS1150E MSRP was $4,400—and brought higher handlebars. And less vibration. One might think that riders of such a speedy machine would like a little protection from the wind, but the truth was—in this painful 55-mph era—that most riders took to the back roads where speeds were generally under 100 mph, and the big bars allowed the rider to muscle the machine around the corners.

Comfy saddle, sensible ergonomics, great power, this was considered one good motorcycle by the go-reasonably fast crowd. The unreasonable crowd wanted the GSX-R.