1981 Suzuki GS1100EX
Claimed power: 105hp @ 8,500rpm
Top speed: 142mph (period test)
Engine: 1,074.9cc air-cooled DOHC inline four, 72mm x 66mm bore and stroke, 9.5:1 compression ratio
Weight (w/half-full tank): 557lb (253kg)
Fuel capacity/MPG: 4.7gal (18ltr)/47mpg average (period test)
Price then/now: $3,999 (1981)/$2,000-$5,000
This Suzuki is one lucky motorcycle. Found in rough condition, unloved, for sale and facing an uncertain future, it had the good fortune of being adopted by Trace St. Germain, perhaps the perfect person to rescue a deserving but shabby Superbike from the 1980s.
Trace originally wanted to buy the bike just for its parts, but ended up with the factory-spec restoration you see here. “I brought the bike home, and I don’t know what got into me. I decided to restore it. It was really badly oxidized, and I had never done a Suzuki before.”
Trace was lucky enough to be born in a motorcycling family. Instead of having to hide his passion from his parents, as many kids did, Trace’s parents encouraged him. “I have been working on bikes since I can remember,” he says. “I mowed lawns to get my first bike, a Yamaha 80 with a stamped steel frame. I rode that thing to death.” The Yamaha was replaced by a Suzuki 250X Hustler and then a Honda 350. Trace also got into racing quarter midgets on the tracks at Sacramento and Baylands in Northern California.
An accident when he was serving in the Army stopped Trace from motorcycling for awhile, but eventually he was able to resume riding. “Sporty, big displacement motorcycles get me going—I like the horsepower,” Trace admits. A Kawasaki Z1R was Trace’s street bike for a long time, and he still has it.
Trace also got back into racing. After trying road racing and other types of motorcycle competition, he settled into drag racing as his sport, starting in 1982 by building a Kawasaki into a drag racer. “I didn’t want to do stupid things on the street, and I enjoy being around drag racing people. People in drag racing help each other. I have given people parts they needed, and they beat me because they had the parts,” Trace says. But that doesn’t stop him helping his competition. “You have a better feeling about yourself,” he adds.
They say good guys finish last, but Trace earned two track championships at the old track in Fremont, California, and has notched seven track championships and one division championship at Sonoma Raceway in Northern California. Continuing the family motorsport tradition, Trace’s son is also drag racing—and winning, with two track championships under his belt so far.
Trace’s interest in mechanics has continued, as well. Now retired, at least from normal work, he’s as busy as he’s ever been, building engines for five drag racing teams. Trace also restores motorcycles for other people with his buddy Brian Jennings, who also paints race bikes. “I like restoring bikes,” Trace says. “It keeps me busy and out of my wife’s hair.”
This Suzuki, however, Trace restored for himself. “Brian and I were going to use this bike as a parts bike. Brian went and looked at it. The bike was rough, and the guy wanted too much money for it, but all the original parts, including about 90 percent of the original nuts and bolts, were in a box. Not only that, there was a good exhaust system that came with it—a Bassani exhaust that would be worth a lot of money on eBay. We finally reached a deal.”
The GS1100 was the top of the line of Suzuki’s extensive lineup in 1980 and 1981. In the previous few years, the company had achieved an impressive comeback, pulling back from the edge of the cliff it had almost ridden over on the back of the failed RE5 rotary. The GS line of 4-strokes Suzuki was selling in the late Seventies and early Eighties were the antithesis of the experimental RE5. Using—and improving—proven technology, Suzuki engineers designed a series of powerful and reliable motorcycles, with understated styling, good handling and decent brakes.
The first two GS models off the line were the 4-cylinder GS750 and the 2-cylinder GS400, introduced in late 1976 for the 1977 model year. Using a new double downtube cradle frame, they were noted for their good handling at a time when most Japanese-built motorcycles were not. When the range-topping GS1000 was added for the 1978 model year, racers quickly found out that it took very little work to get a whole lot of power out of the engine. A racer based on the GS1000 and tuned by “Pops” Yoshimura won Daytona and the Suzuka 8 hours race in 1978, and the AMA Superbike championship in 1979 and 1980.
Development never stands still, and in mid-1978 Suzuki engineer Sadao Shirasagi was assigned the task of upgrading the GS 4-cylinder engine. His goal was to improve fuel economy and lessen emissions, as well as improve performance across the powerband. To that end, Shirasagi employed 4-valves per cylinder to speed up the entry and exhaust of fuel mix in and out of the cylinders. The aim was to squeeze as much energy as possible out of each gasoline droplet.
The design Shirasagi developed was called Twin Swirl Combustion Chamber, or TSCC. A ridge in the cylinder head combustion chamber roof effectively divided the chamber in two, with one intake and one exhaust valve on either side. This ridge directed the intake charge into two controlled circular swirls, and a squish band in the chamber helped accelerate the motion. The centrally located spark plug allowed even burning of both swirls of fuel/air. The result was not only complete combustion of the fuel/air mix, but an engine that could tolerate high compression on a lean mixture.
Shirasagi’s TSCC cylinder head was featured on the new for 1980 GS1100, which replaced the top of the line GS1000. Unlike the previous big GS, Shirasagi’s new engine used dual overhead camshafts operating on forked rocker arms instead of shimmed buckets. This greatly improved ease of maintenance, as valves could now be adjusted with a wrench and screwdriver instead of the far more time-consuming shim replacement required previously. The GS1100 also featured electronic ignition, an air-charged front suspension and something rarely found on a performance motorcycle—a comfortable seat. Cycle Guide called it “one of the best riding, most comfortable motorcycles ever built.”
Contemporary testers praised the ease of keeping the GS on a line through a corner—“It will corner with the best of its rivals and outdo the rest,” Cycle said—and they had a lot of fun playing with all the suspension settings. The air-assisted forks featured a single, easily accessible air valve, plus adjustable damping and adjustable preload. The rear shocks had five preload positions and four positions for rebound damping. It was without question the most tunable factory suspension ever offered.
Unfortunately, adjusting fork preload required removing the handlebars, which induced more than a few gripes. Other mild gripes involved an inability to aim the headlight beam, carburetion problems under light throttle, the lack of a petcock and leaky valve covers. The single biggest complaint centered on the bike’s hyper-sensitive carburetion, which some riders found impossible to ride around. “At every expansion joint the throttle snaps open a millimeter, enough to make the bike rear up and accelerate,” Cycle Guide complained.
But back on the plus side, the big GS1100’s brakes were considered among the best in the business. And while testers liked the suspension, they loved the engine. “Any motorcycle that has effortless power at 3,000rpm—which the Suzuki does—is very likely to have eye bulging top-end as almost a casual and incidental by-product,” Cycle said in its December 1980 road test. Cycle Guide concurred, stating simply, “It flat does what you ask of it.” And it did.
For 1981, Suzuki had the demanding task of bettering the obviously excellent 1980 model. Aside from a change in paint colors, there was a slight change in valve seat angles (60 degrees instead of 75 degrees for the first cut, for better intake charging), a fuel petcock was added along with a gas reserve, alternator output was increased and the rather busy instrument display received minor changes such as the addition of a sidestand light.
Cycle Guide conducted a comparison test for its July 1981 issue, pitting the Suzuki against a Honda CB900F and a Kawasaki GPz1100. The GS was the favorite for touring on freeways with its comfortable seat, adjustable suspension and roll-on ability in high speed passing, but got marked down in around town riding for its low-speed carburetion problems. On a twisty mountain road, the GS led the pack for its cornering prowess. The one place the GS really fell behind was at the race track. “The GS wanders and feels vague when pushed through fast turns,” Cycle Guide’Cycle Guide concluded.
Up to this time, Suzuki had concentrated on engineering to the exclusion of style. In 1981, the company contracted former BMW designer Hans Muth for a radical redesign of the GS. The Katana version of the GS debuted in 1982, and while not universally loved, its space-aged, avant-garde styling turned heads and sparked discussion. The GS range continued on for a few more years before being replaced by the brilliant GSX-R range.
Smart owners hung onto their GSs, and many are still running today. The big GS Suzukis have earned a reputation for bomb-proof reliability, in large measure because the engine was overbuilt. The crankshaft of the GS engine ran in roller bearings, a design that, while expensive to build, lends itself to long engine life thanks to its resistance to uneven loads. Helping things, the engine’s low-pressure lubrication system worked well, even when operating in less than optimum conditions.
Trace builds bikes to Antique Motorcycle Club of America standards, which means the markings on the bolts have to be the same as the factory bolts and the cable routing has to be the same as the factory. In other words, it has to be factory correct. “The hardest part was making sure all the bolts were correct,” Trace explains. “There are a lot of new-old-stock parts for GS Suzukis out there, but bolts are hard to get. Ninety percent of what I needed came with the bike, but of course the other 10 percent were hard to find. Eventually, I collected all the original bolts. I had to re-zinc plate a lot of them, and the bolts for 1981 Suzukis came in an odd green/black color. I had to reproduce that.”
If you are going to restore to factory specs, you first need to know what those specs are, and Trace lucked out. “I had enough resources to make sure I got the assembly right. Ray Rains and Woody [Kahea Woods] helped with the correct bolts and a lot of little things. Suzuki published excellent documentation, so I knew where the cables were routed and where to put the clamps,” Trace says. Brian Jennings did the paint, matched to a spot of the original paint on the bike. Trace’s efforts paid off with the award for Japanese 2nd Place at this year’s The Quail Motorcycle Gathering.
Despite careful attention as the bike went together, Trace’s first ride out was somewhat disappointing. “I didn’t like the factory bars. It felt like I was driving a bread truck. And the brakes felt mushy,” Trace says. “I had to fix an oil leak from the cam chain tensioner. There’s a little seal—which you can’t find any more—that is leaking. I made a new seal, and we will see if it works. I had to re-jet the carbs. I also haven’t been able to find the right hot press seat cover and had to settle for a stitched one.” Trace has recently found the correct seat cover, although it wasn’t installed for our photo shoot.
After some suspension tuning, handlebar adjustment and a brake line swap to improve performance, Trace was a lot happier. “The bike rides a lot better now that I had a chance to set the handlebars, shocks and forks up more to my liking. The bike is really nimble. It seems like it would be a nice cruiser. I really want to take it out on the road, but not on a really tight mountain road. That’s the problem with big bikes—on a tight road, you never get out of second gear.” And while that may be true, it doesn’t dampen Trace’s enthusiasm for the big GS. “As soon as the weather warms up, I am going to put a lot of miles on this Suzuki.” MC
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