1975 Suzuki GT550 Indy

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The 1975 Suzuki GT550 Indy.
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1975 Suzuki GT550 Indy.
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1975 Suzuki GT550 Indy
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The Suzuki GT550 featured Suzuki’s Ram Air cooling system, which, according to a period ad, “... works exactly like it’s name implies — it forces cooling air down and over the cylinders. So the 550 won’t lose any of its 50 horses from engine heat distortion.”
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Although Zeki Abed enjoys riding each and every one of the 13 motorcycles in his collection, his 1975 Suzuki GT550 Indy gets ridden a little more than the rest of them.
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An old Suzuki GT550 Advertisement.
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The Suzuki GT550 featured Suzuki’s Ram Air cooling system, which, according to a period ad, “... works exactly like it’s name implies — it forces cooling air down and over the cylinders. So the 550 won’t lose any of its 50 horses from engine heat distortion.”
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1975 Suzuki GT550 Indy.

1975 Suzuki GT550 Indy
Claimed Power: 50hp @ 6,500rpm
Top Speed: 115mpg (period test)
Engine: 544cc 2-stroke air-cooled inline triple
Weight (wet): 481lb
MPG: 40-50mpg
Price then: $1,595
Price now: $1,500-$3,000

The 1975 Suzuki GT550 was the mama-bear-sized version of Suzuki’s GT range of touring and commuting two-stroke triples. Unlikely to get you in trouble and most certain to get you home, Suzuki’s GTs were the thinking person’s two strokes.

In the early Seventies, Suzuki’s flagship bike was the Suzuki T500 Titan two-stroke twin, a good, reliable, eminently rideable motorcycle that, even if it was being raced successfully, lacked the exciting qualities of some of its competitors. This was the era of Superbike — exciting, gorgeously styled, fast, powerful motorcycles. If Suzuki was going to stay in business, it needed a Superbike, and the Titan wasn’t it.

Triple Treat

The design Suzuki came up with for its Superbike was both clever and innovative: The engineers added a third cylinder to the existing twin and solved cooling problems by designing a compact water cooling system.

The result was launched at 1971’s Tokyo motorcycle show. The bike was officially cataloged as the Suzuki GT750 but unofficially labeled in the United States as the Water Buffalo. The Water Buffalo was well thought out, reliable and, unlike previous Suzukis, powerful. Heavy for its size, it was nevertheless a good touring machine, smooth and relatively quiet for a two stroke, with a rubber-mounted engine. Later models received disc brakes and constant velocity carburetors.

In early 1972, Suzuki announced a smaller triple — minus the water cooling but boasting a six-speed gearbox. The Suzuki GT380 had cubic capacity of 371cc and produced (according to Suzuki) 38 horsepower at 7,500rpm. A cast shield over the top of the cylinder heads — designated the Ram Air System by the advertising department — directed more air past the fins for better air cooling.

A few months later a third Suzuki triple, the Suzuki GT550 Indy, appeared in showrooms. Bore and stroke were an almost square 61mm x 62mm, giving a capacity of 544cc. Compression ratio was 6.8:1 and claimed horsepower was 50 at 6,500rpm. The five-speed transmission was operated via a multi-disc six-spring clutch.

Like the GT380, the Indy also had the Ram Air cooling system. The concept was technologically interesting, and attracted the attention of a lot of enthusiasts, including one teenage kid. “This bike was the bike I always admired in high school,” Suzuki GT550 owner Zeki Abed remembers, adding, “I always liked bikes that were a little different than the rest.”

Inside the Suzuki GT550

The engine boasted numerous interesting technical touches. Like most two strokes of the time, the Suzuki GT550 featured automatic oil injection, with a separate tank for oil below the seat with delivery pipes feeding the rear of the pistons. Oil was metered to the cylinders, and any oil not burned in the combustion chamber drained down into the crankcase, and from there was forced through a check valve into the transfer port of another cylinder. This system lessened the blue haze that tends to float out the pipes of two strokes, and improved oil mileage.

The connecting rods used caged needle bearings at each end, and the center cylinder exhaust split into two pipes, each with its own muffler. A reliable electric starter was backed up with a kickstart in case the owner managed to run the battery down, despite a capable charging system.

A double cradle frame helped aid steering rigidity, while rubber engine mounts cut vibration. Suzuki claimed the four-pipe exhaust added torque, although many people thought the main purpose of all that plumbing — with eight separate joints — was more cosmetic. A double-sided twin-leading-shoe front brake added stopping power.

Period magazines lauded the Indy’s quiet running, good handling and smooth acceleration, but they also noted a persistent whir from the primary drive and a distinct clunk when shifting from first to second gear. Testers thought the problem was due to the wide gap between first and second. Lights were big and bright, and oil and gas consumption were considered excellent for a two stroke: 44mpg and 600 miles per quart of oil.

The one major problem with Suzuki’s mid-size triple had nothing to do with its technological excellence. Rather, the magazines regretfully concluded, Suzuki had once again failed to design a sexy motorcycle. The GT550 wasn’t sportingly styled or screamingly fast.

“It’s really, really good,” one reviewer said, adding, “But what makes it good is invisible, hidden under the tank and between the engine side covers and inside the oily recesses of the mufflers. What makes it good is difficult to photograph and difficult to write ad copy about and more difficult still to sketch out a convincing case for your buddies.”

Despite the GT550’s perceived lack of sex appeal, it found its niche as a get-to-work and lightweight touring bike; it was reliable, economical and made for back road cruising. It won a 1976 Cycle shootout against faster and more stylish competitors, simply because it was so good in so many ways. Suzuki priced the GT attractively, and it was reasonably successful.

Changes to the model were few. The GT550’s front drum gave way to a single front disc brake for 1973, and for 1974 the exhaust system was redesigned to increase ground clearance. Along the way the forks lost their gaiters and the steering damper, and the carburetion was modified to reduce intake noise. However, as one period report noted, “Despite the fact that the 550 has been subjected to minimal development work since its introduction four model years ago, it has an agreeable texture which suggests the design team got it right the first time, and has had the good sense to leave it alone.”

Meanwhile, Suzuki had become enmeshed in an expensive experiment with the Suzuki RE-5 rotary motorcycle. The RE-5 was a market disaster and the development costs nearly sank Suzuki. Luckily, the company designed some very good four-stroke bikes at the same time it was wrestling with the rotary engine. With the new four strokes ready to go and emissions regulations on the horizon, Suzuki discontinued its two-stroke line. The last year for the Suzuki GT550 was 1977.

Zeki Abed’s Suzuki GT550

Zeki Abed has 13 motorcycles and loves them all. But like many collectors who also ride their bikes, Zeki find himself riding some more than others. “I try to ride them all, but this GT550 tends to get ridden a little more. With a push of the button, the beautiful smell of two-stroke oil wafts out of the four mufflers. It warms right up, never overheats and is very quiet for a two stroke.”

Back when the Suzuki GT550 was new, Zeki couldn’t afford one. Instead, he worked odd jobs until he saved up enough to buy an older Suzuki T350 twin. It wasn’t quite as nice as the GT550 of his dreams, but it was a good start. After that came three Honda 400 Fours and a heavyweight Kawasaki KZ750 L3 during college.

By the late 1980s, Zeki was not entirely happy with his contemporary four-stroke motorcycles. “I missed the ring-ding of the old two strokes,” he remembers. In 1991, he found a mint RZ350, which he rode for a few years but sold for financial reasons. That was followed by a few years without any bikes at all.

In 2001, Kawasaki’s big 1,100cc ZRX caught Zeki’s eye, but soon that old two-stroke yearning resurfaced and a mint 1979 Daytona found its way into his garage. He got the eBay bug, and the old bikes started flowing. Zeki has bought 20 over the last nine years, including Yamaha RD400s and R5s, and Kawasaki triples — but something was missing.

Remembering the Suzuki he had loved as a teenager, Zeki went looking for a Suzuki GT550 and found our feature bike, a disc-braked 1975 GT550M. “It was an original condition New York City bike that had spent its winters indoors. When it arrived at my door — I don’t know how they did the photos, but it wasn’t quite as pristine as it looked in the pictures. I looked at it. I thought about it. I decided to keep it and just ride it around.”

A few months later, Dennis Castner visited Zeki to buy two of his Yamahas R5s. When Dennis saw the Suzuki, he told Zeki he restored motorcycles. They struck a deal for the GT550’s restoration, and Zeki helped Dennis load the Suzuki on the trailer with the R5s.

Dennis started working on the bike, inundating Zeki’s e-mail inbox with photographs to show progress. Dennis had the frame powder coated, he rebuilt the engine, and cleaned and polished the cases.

Both Dennis and Zeki hunted for parts, and Dennis found some new-old-stock rims and rebuilt the wheels. Up to this point the restoration had been financially reasonable, but the devil is in the details, and detailing the Indy to its showroom stock glory was starting to add up.

“I told Dennis to replace all the rubber, including the rubber parts in the carburetors, the linkage, mounts and cable shrouds. Dennis’ brother worked at a Suzuki dealership, and this was the perfect connection. He was able to locate many hard to find parts to complete the bike,” Zeki says. But even with that connection, restoring the pipes proved to be the hardest part of the Suzuki’s revival. “We couldn’t find a good set of pipes. I went through three sets of pipes that I found on eBay, trying to get a set good enough to use. I realized I really wanted this to be right.”

When Dennis finally delivered the Suzuki GT550, Zeki found himself with a machine that was not only pretty, but also an all-around performer. “I just connect the battery, give it a little choke and it starts right up,” Zeki says. The Indy is equally happy taking its owner to the grocery store as it is spending all day on a country road. “The slow-speed handling and brakes are good for its era. The power band seems broader and more civilized than some of the other two strokes I own. The bike is not jerky, accelerates smoothly and comfortably purrs along the freeway at a leisurely 65 to 75mph. It has the feel of a much larger motorcycle.”

Zeki continues, “This bike enjoys canyon carving at a brisk pace. You can lean it over, and it transitions smoothly from side to side. It has adequate clearance despite the three-into-four plumbing. It also stops pretty well — that front disc works well for its era.” Maintenance is fairly normal for a bike that is not a daily rider. Zeki keeps his GT covered indoors, changes all fluids on a regular basis and uses additives such as Seafoam to keep the carburetors clean. He checks the tires for weather-checking and tire wear and disconnects or tends the batteries to preserve its life.

Thirty-five years after it was built, the unlikely two stroke has become an unlikely collector’s item. Most collector motorcycles are visually striking. When it was built, the 550 Indy was a consumable, a durable, technologically interesting but plain bike. Even with the passage of years, its most interesting features are still its engineering details, not its looks. “Except for that Ram Air shroud,” Zeki adds. “It’s the one sexy thing about the bike.”

More importantly for Zeki, perhaps, is the fact the Suzuki GT550 recalls a particular point in time. “This is the bike I always admired in high school,” he explains. “But what I like about it now is that it is dependable and comfortable — it’s both collectible and enjoyable.”



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