The Suzuki GR650 was introduced in IFMA motor show in Cologne, West Germany, in September 1982. A few months later, in March 1983, it was launched in its home land, Japan. In the United States it was called the GR650 Tempter, and was only sold there for the 1983 and 1984 model years. Suzuki would later use the `Tempter' name on a version of the ST400 sold in Japan and Europe.
It was a relatively light motorcycle. Suzuki boasted that they created a machine that is as light as a 400cc but can perform like a 750cc. Its dry weight was 178 kg, same as Suzuki's 1984 water-cooled four-cylinder GSX400FW.
The GR650 offered a lower price than its rivals and a body as lightweight as a 400cc class motorcycle, while incorporating cutting-edge technology in its engine, chassis, and suspension systems.
Instead of a water-cooled inline-four, the GR650 was powered by aa air-cooled parallel twin, a four-stroke DOHC machine with two valves per cylinder. The engine featured a new design called the High Power Inlet Path, which increased intake airflow velocity and improved cylinder filling efficiency, reducing torque dips. An oil jet cooled the back of its pistons by spraying oil from a nozzle located on the back of the crankshaft bearing. DOHC camshafts were hollow, reducing rotational mass, and a single-axis balancer was added to the 180-degree crank phase to reduce vibrations.
The twin-dome combustion chamber (STDCC) of the Suzuki Twin Dome Combustion Chamber incorporates the AI (Air Induction System). The AI is a mechanism that generates a swirl (vortex) using an air jet to achieve an ideal air-fuel ratio.
With the GR650, Suzuki was first to adopt a variable crankshaft mass mechanism to achieve both easyier take-off characteristics at low revs and improved responsive power at higher revs. The engine featured a two-stage flywheel which used a centrifugal clutch to disengage an auxiliary mass that rotates together with the crankshaft up to approximately 2500 rpm, and separates from the crankshaft at approximately 3000 rpm or higher, effectively lowering the mass of the flywheel.
The chassis of the GR650 featured a double-cradle frame made of thin-walled, high-tensile steel tubing, paired with an aluminum square-tube swingarm. The frame was combined with a full-floater rear suspension, first adopted by Suzuki's RM series motocross bikes at the time. The rear suspension was equipped with RCPL (Remote Control Preload), a spring initial adjustment function that could be adjusted while riding. The bike was equipped semi-air suspension at the front.
The design of the GR650 was somewhat of a compromise between an ”American style” cruiser and a naked sports bike. The riding position was relaxed and upright and the seat looked like it belonged to a cruiser – but shape of the fuel tank and the star cast wheels were more modern.
Incidentally, the North American version of the GR650 was available with cast wheels (GR650) and wire spoke wheels (GR650X), and featured a ”Tempter” emblem on the side cover. Both the domestic and international versions of the GR-650 had city lights (position lights) mounted below the headlight. The differences between the domestic and international versions are the shape of the light bracket and the omission of side reflectors.
The domestic (Japanese) version had a dry weight of 178kg, while the export version had a dry weight of 184kg. The spoke wheel version was 3kg lighter at 181kg. The specified seat height was also different. The export version was said had a seat height of 760 mm, compared to 770 mm for the domestic version.
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