The Bimota Tesi (translated: "Thesis") is a motorcycle model in the superbike class, produced by the Bimota company of Italy. It is distinctive for its front wheel being mounted via a swinging arm arrangement with hub-center steering, unlike the telescopic forks more common in modern motorcycles.
Summary While the prototype Bimota Tesi was unveiled in 1983, it was not until 1990 that a road-legal version was commercialized—the Tesi 1/D. The lineage was discontinued in 1994. The model line resurfaced in 2002 with the Tesi 2/D, developed by an Italian tuner who marketed it under his name (Vyrus 984 C³ 4V). This was followed in 2007 by the Tesi 3/D, ensuring the model's continued existence.
The main innovation of the Bimota Tesi is its use of a swingarm and hub-center steering system instead of a conventional telescopic fork. This design is intended to eliminate the "dive" effect of traditional forks under braking and to provide improved stability.
Many Tesi models have been powered by engines from different manufacturers. The early prototypes were equipped with Honda and Yamaha engines, but Ducati was ultimately chosen for the final prototype and all production models up until 2015. Kawasaki later took over, supplying the engine for the Tesi H2. The Tesi was also fitted with the 500 V-Due engine.
Unlike Bimota’s usual naming convention—where the first letter represents the engine manufacturer, the second stands for Bimota, and the number indicates the model’s order of release—the Tesi series follows a different pattern. The initial research leading to the Tesi began when engineering student Pierluigi Marconi, for his university thesis at the University of Bologna, drew inspiration from engineer Difazio's work to develop a motorcycle where the steering and front suspension would be independent. He named the resulting bike Tesi, meaning 'Thesis' in Italian. The letter D stands for the engine manufacturer, and the number represents the model's generation. The first Tesi developed after Kawasaki's investment in Bimota was called the Tesi H2, as it inherited the Kawasaki Ninja H2 engine.
Architecture
The telescopic fork, found on most road motorcycles, combines both steering and suspension, meaning that any movement of one affects the other. Engineer Difazio's design completely separates the two functions, eliminating their negative interactions. As a result, the bike’s attitude remains unchanged during braking, unlike with a conventional fork. This setup also allows for geometry adjustments (such as wheelbase and rake) without affecting handling dynamics. While this concept had previously been tested—particularly by ELF—it had never before been applied to a road-legal motorcycle. With the Tesi, Bimota brought this innovation to a production model.
The front and rear swingarms are connected by an omega-shaped frame. The wheel hub houses two tapered bearings and an axle, which is connected via a linkage system to a small steering column located against the frame on the left side of the bike. Another linkage connects this column to the lower triple clamp and clip-on handlebars.
The frame itself is reduced to two side plates and two subframes—one at the front to support the fuel tank and handlebars, and one at the rear for the seat unit—resulting in significant weight savings.
However, this architecture requires an extensive number of components to assemble the front suspension system, increasing manufacturing costs. These components must also be heavily reinforced to withstand the forces generated under braking. Additionally, the swingarm increases the turning radius, making maneuvering more difficult. This issue was mitigated in the Tesi 3/D, which features a tubular trellis swingarm, allowing for smaller-diameter tubes without compromising rigidity.
Development The first prototype was presented at the Milan Motorcycle Show in 1983. At that time, it was powered by a Honda VF 400 F engine, and its frame was a carbon fiber monocoque positioned under the engine. The bike had a futuristic design and introduced a hydraulic steering system known as DCS (Dive Control System). This system used two pistons: one on the left side of the wheel and another under the handlebars. When the rider turned the handlebars right, the second piston pushed hydraulic fluid through a hose, compressing the wheel piston. When turning left, the fluid was directed into a second hose, causing the wheel piston to extend.
The following year (1984), Bimota entered a second prototype into the Austrian and Italian rounds of the World Endurance Championship. This version was powered by a Honda VF 750 F engine, producing 90 hp at 10,000 rpm, sourced from Honda's racing division. The frame was upgraded to a hybrid structure made from aluminum alloy, carbon fiber, and Kevlar, supporting the engine. In 1985, this was replaced by two Peraluman 35 omega-shaped beams, encircling the engine from below. While the hydraulic steering system remained, it severely affected maneuverability, making the bike almost impossible to ride at any speed.
In 1987, a new prototype powered by a Yamaha 750 FZ engine marked a significant improvement. The hydraulic steering system was abandoned, and replaced by a linkage system, making the bike much easier to handle. By 1988, Bimota chose Ducati as the engine supplier for the Tesi. Ducati’s engine casings provided better structural rigidity, making them ideal for the Tesi's design. This resulted in a final prototype, which differed from the production model only in its exhaust silencers.
Engine An initial model was powered by a Yamaha FZ750 engine; subsequently Honda V-4 and then Ducati V-Twin motors were adopted; in the wake of the takeover of Bimota by Kawasaki in 2019, since 2020 they have used motors by Kawasaki.
Models Bimota produced the first Tesi in 1984. As of 2017, 18 generations of Tesi had been produced. Subsequent models have included the Ducati-powered Tesi 1D, Tesi 2D, Tesi 3D and the Bimota Tesi H2 (2020).
Tesi 1/D
Mechanics The first road-going Bimota Tesi, the Tesi 1/D, was unveiled at the 1990 Cologne Motorcycle Show. Its design was entrusted to Massimo Tamburini. The bike was powered by a Ducati 851 V-twin, four-stroke engine, featuring Weber electronic fuel injection with two injectors per cylinder. It produced 102 horsepower at 9,500 rpm.
Because the suspension was highly sensitive to minor adjustments, it required high-quality shock absorbers. Marzocchi components were chosen for this role. The rake angle could be adjusted by up to 30°. Braking was provided by Brembo with two 320 mm front discs and a 230 mm rear disc. The three-spoke aluminum wheels were made by Marchesini.
A second version was released a few weeks later, featuring an increased engine displacement of 904 cm3. The stroke was lengthened by 4 mm, raising power output to 113 horsepower at 8,500 rpm and giving the bike a top speed of 250 km/h. It was priced at €22,810.
Bimota produced 127 units of the 851 cm3 Tesi and 20 units of the 904 cm3 version. Nearly all were white and red with three green stripes at the bottom of the fairing. Only one was entirely red, while another, used for official photos, had more red on the fairing. In promotional brochures, these bikes were labeled Tesi 1/D 851 and Tesi 1/D 906, respectively.
Variants
Tesi 1/D SR
In 1991, the Tesi 1/D SR replaced the original model. It retained the bored-out Ducati 851 engine but had a dry weight of 188 kg, with a 4-liter reduction in fuel tank capacity. The suspension system was upgraded to Öhlins. A total of 164 units were produced, each selling for €22,946. The color scheme changed slightly: it remained white and red, but now featured green circles on the top of the fuel tank, behind the seat, and on both sides of the front fender.
Tesi 1/D ES
To celebrate Bimota’s 20th anniversary, the Tesi 1/D ES (Edizione Speciale) was introduced at the 1992 Cologne Motorcycle Show. The design, now more fluid and refined, was created by Giorgetto Giugiaro.
Mechanically, the Tesi 1/D ES differs from its predecessors with a front swingarm machined from solid aluminum instead of being forged, as well as a front shock absorber specifically designed for the Tesi at Öhlins by a former Grand Prix rider. The Weber electronic fuel injection system was replaced by a Bimota-designed system. The engine produces 117 horsepower at 9,000 rpm, and the wheels are made by Akron.
Only 50 units were produced, each priced at €23,335.
Tesi 1/D EF The Tesi 1/D EF (Edizione Finale, or Final Edition) was introduced at the 1994 Cologne Motor Show. This final evolution was essentially a Tesi 1/D ES, but available exclusively in an anthracite gray livery with orange pinstripes. Only 25 units were produced. The first unit was delivered to Italian journalist Giorgio Sarti, a major Bimota collector and author of a reference book on the brand. This particular model featured a semi-fairing, which exposed the two omega-shaped aluminum plates that form the Tesi’s frame, as well as the complex front suspension system. The exhaust silencer was covered in carbon fiber. It was sold for €25,265.
The last models of the Tesi 1/D ES, as well as the Tesi 1/D EF, were equipped with a final drive chain tension adjustment system using a push wheel, whereas earlier models retained the eccentric adjustment system found on the standard Tesi 1/D and Tesi 1/D SR.
All Tesi 1/D models featured the "Tesi 1D" inscription on the seat flanks. Within the "D", the specific model name was written: SR or ES. On the Tesi EF, the "D" contained the letters ES, while the Tesi 1/D 906 bore the "SR" inscription.
Tesi 1/D 400J Japan received a special Tesi model, designed to comply with local homologation regulations. The Tesi 1/D 400J was powered by a 400cc engine derived from the Ducati 400 SS. The frame was slightly different, with a narrower omega-shaped arch due to the smaller engine size. Production lasted from 1992 to 1993, with 50 units built. The color options included red, white, and blue, and the bike featured the "Tesi 1D" monogram on the fairing sides and "400" on the seat flanks.
Tesi 1/D Folgore Bianca In 1991, the Japanese tuner White House introduced the Tesi 1/D Folgore Bianca. This version featured a different fairing design. A total of 30 units were produced, with five based on the Tesi 1/D 400J, five on the Tesi 1/D 906, and twenty on the Tesi 1/D 851. Owners of the first two versions could choose their own color schemes, while the third version came in a pearl gray finish.
Competition Between 1991 and 1993, the Tesi competed in the Italian and World Superbike Championships, as well as the Italian Sport Production Championship. The racing version was equipped with a 964cc engine, achieved by increasing the bore diameter by three millimeters. It produced 132 horsepower at 10,500 rpm.
The following year, Bimota entered a Tesi 500, powered by a 500cc two-stroke V-twin engine, a precursor to the V-Due. The fuel injection system was linked to an ECU, which adjusted the fuel supply based on air temperature, coolant temperature, exhaust gas temperature, and airbox pressure. Fuel was injected at the optimal moment when the exhaust port was fully closed. This engine produced 124 horsepower and was mounted on a standard Tesi frame. The rear disc brake was increased to 210mm, and the exhaust silencers were made from carbon fiber.
The bodywork was painted white, with red and turquoise blue stripes. The seat flanks bore the "Tesi 500" inscription in white, while the yellow number plates were positioned on the front fairing and seat cowl. On two of these bikes, the front fender was entirely red.
Another Tesi 500 variant featured a black-painted fairing, a yellow seat cowl with a black number 7, and a yellow upper front fairing, all accented with red flame graphics.