Liquid Cooled Pioneer: The Suzuki GT750
The Suzuki GT750 is one of the most beloved Japanese bikes of all time. Released in the early 1970s during the formative age of the superbike, the GT750 was designed primarily as a sports tourer. Its smooth acceleration and comfortable ride made it a more refined alternative to the Kawasaki Z1 or Honda CB750.
But what really earned the Suzuki GT750 a prominent place in motorcycle history was its innovative engine. The GT750 was the first Japanese motorbike to employ a liquid cooling system for the engine rather than the traditional air-cooled setup. While this added plenty of refinement to the engine performance, it also earned the GT750 some affectionate nicknames. American gear heads called it the “Water Buffalo” due to its heavy bulk, while UK enthusiasts labeled it the “Kettle”.
Despite its laidback image, the GT750 could really eat up the miles thanks to its engine. Rather than directly competing with Honda and Kawasaki for pure performance, Suzuki designed the GT750 to have exceptional acceleration. This made it the perfect bike for long road trips.
In this piece, we'll take a ride through the history of the GT750 to find out why this Japanese tourer has earned its legendary status.
Development & History
Before the release of the Suzuki GT750, the standard practice among Japanese motorcycle manufacturers was to use air cooling to lower engine temperatures. These engines left a series of fins on the body of the engine open to the air. The idea was that the constant airflow around the engine and the large surface area of the fins would dissipate heat.
However, air-cooled engines tend to have one major drawback – engine noise. This wasn't as much of a problem for performance bikes like the Kawasaki Z1. But when trying to create a refined sports touring bike that's meant for relaxed cruising, it's not ideal.
To provide the best riding experience possible, Suzuki designed the GT750 with liquid cooling in mind. As a result, the GT750's engine ran a lot quieter than the air-cooled motors of its competitors. With its release in 1971, the Suzuki GT750 became the first liquid-cooled motorbike from a Japanese manufacturer.
Another feature designed to generate a pleasurable riding experience was the Suzuki Recycle Injection System (SRIS). This innovative system recycled leftover oil within the crank chambers to cut down on exhaust fumes. No manufacturer had ever applied these kinds of features to a two-stroke engine before.
Powered by a 739 cc inline three-cylinder, two-stroke engine that delivered 67 horsepower and a top speed of 110 mph, the GT750 was a touring bike through and through. A comfortable seat completed the design as Suzuki went in a different direction to Honda and Kawasaki.
In 1973, a raft of improvements began to emerge. More chrome plating was added across the bike and the single front drum brake was replaced by a disc brake system. At the beginning of 1974, Suzuki's engineers raised the power level to 70 horsepower. In 1975, the GT750 came with silenced exhausts, some extra power, and a new top speed of 120 mph.
After five years in production, the GT750's run ended in 1977. But the Suzuki GT750 continued to be a popular model on the used market and is still coveted by motorcycle enthusiasts today as one of the iconic classic Japanese touring bikes.
The strength of the Suzuki GT750 is its smooth, powerful engine. While Honda and Kawasaki released full-throttle superbikes focused on performance, Suzuki prioritized smooth acceleration and riding refinement. The main claim to fame for the GT750's engine is Suzuki's decision to abandon air-cooled engines in favor of a liquid cooling system.
This gave the GT750 an engine that produced less noise than its competitors, allowing for a more comfortable riding experience. In the same vein, Suzuki also fitted their SRIS feature to reduce exhaust fumes. But what really makes a touring bike fun to ride is its engine, which needs to be smooth and capable of potent acceleration.
Suzuki's GT750 could do just that. The three-cylinder inline two-stroke 739 cc engine produced 67 horsepower when first released. But more importantly, it could provide around 56 lbs-ft of torque. With a top speed of 110 mph, the GT750 wouldn't be winning a quarter-mile against its competitors. But it did provide plenty of usable performance while on the highway.
There's another reason why the Suzuki GT750 needed so much torque – it was a big-bodied, heavy touring bike. The GT750 weighed in at 470 lbs (214 kg) at dry weight. Likely caused by the liquid cooling system and the features added on for riding comfort, the GT750 needed plenty of grunt to get itself moving.
On the open road, critics and owners alike praised the engine's smooth power delivery and mile-munching capabilities. The GT750 was a comfortable cruiser, capable of accelerating quickly even in a higher gear at low rpm. Even at 60 mph on the highway, the GT750 was perfectly happy sitting under 4000 rpm.
Suzuki introduced various engine improvements across the GT750's five-year production run. Initial models connected the two exhausts on either side of the bike together for better performance at low revs. The five-speed gearbox was relatively smooth, offering good performance.
The power output increased to 70 horsepower in 1974, with a little more power following in 1975 for a total of 73 horsepower. Top speed was upped to 120 mph by the end of the GT750's sales lifespan.
While it was never going to be nimble enough to compete with the likes of a Honda CB750, the Suzuki GT750 offered enough control as a sports tourer. The immense weight of the GT750 compared to its rivals took away some mobility, but the rest of the bike was capable of handling its 470 lbs bulk.
High-speed stability while cruising was the name of the game with the GT750, not slaloming around a race track. The bike featured a 57.5 inch (1460 mm) wheelbase, the same as a Honda CB750. This provided adequate support for the heavy GT750 on the open road.
In its first model year, the Suzuki GT750 featured a double-sided front drum brake designed with a twin-leading shoe. The rear also featured a drum brake. These could stop the bike, but some riders commented that the brakes felt too soft.
Suzuki remedied this in 1973 by replacing the front drum brake with two disc brakes. None of Suzuki's rivals provided a duo of front disc brakes, giving the GT750 plenty of stopping power compared to other bikes. The rear brake remained as a drum brake for the rest of the GT750's production run.
A big factor in the success of a sports touring motorcycle is the riding position. Suzuki fitted a wide, comfortable seat to the GT750 to provide maximum comfort. Most riders found this setup adequate, including the position of the handlebars. Some riders were less complimentary, but for the most part, the Suzuki GT750 was comfortable to ride.
In 1974, Suzuki's engineers removed the pipe that connected the two exhausts to allow for a better lean angle and road clearance. Handling performance was improved even further in 1975 after several tweaks to the engine's construction. This was achieved even though the bike's dry weight had ballooned to 507 lbs (230 kg).
Despite its heavy weight, the Suzuki GT750 was still capable of the smooth, easy acceleration that made it an iconic Japanese sports tourer. Thanks to gradual improvements to the brakes and suspension, the GT750 has developed great staying power as a desirable classic.
Impact On Motorcycle Culture
Honda, Kawasaki, and Suzuki had been three of Japan's most prominent motorcycle manufacturers for decades by the mid-1960s before a new age dawned for motorcycling. By the early 1970s, Honda and Kawasaki had led the way in creating 750 and 1000 cc “superbikes” - designed to bring racing levels of performance to the highway.
But Suzuki chose a different route for their 750 cc model, and the GT750 was designed as a long-distance sports touring bike rather than a superbike. The decision paid off, and Suzuki's bold direction netted the GT750 plenty of die-hard fans. Even today, these bikes are still highly prized models in the eyes of classic bike collectors and motorcycle enthusiasts.
Suzuki pioneered several innovations with the GT750, with the liquid cooling system being the most recognized. The GT750 was the first Japanese production bike to use a liquid cooling system rather than the ubiquitous air-cooled setups used on its main rivals.
While this did add weight, it improved cooling efficiency and reduced engine noise – making for a much more refined riding experience befitting a touring motorcycle. Suzuki also used an oil recycling system, the SRIS, in another first for a Japanese bike. This cut down on exhaust fumes, adding to the bike's refinement. The GT750 was also the first bike to provide two front disc brakes.
The GT750's three-cylinder inline engine also won the model plenty of fans. While it couldn't match the outright power of the Kawasaki Z1, it was designed more for powerful acceleration rather than pure performance. Thanks to its smooth power delivery, the two-stroke engine was perfectly matched to the GT750's role as a tourer.
Suzuki GT750's are still sought after today on the classic motorcycle market. Gear heads across the globe still dream of touring the highways on this legendary Japanese motorcycle.