Motorcycle specifications Bimota750 HB1 1973 The first Bimota

In the early 1970s, the motorcycle world was in the midst of a revolution. Japan, with the Honda CB 750 Four, introduced the concept of the "superbike" to the general public: a powerful, reliable and affordable 4-cylinder engine. However, its power was contained within a chassis that struggled to keep pace. This gap between engine and chassis gave rise to one of the world's most exclusive and respected brands: Bimota. And its very first creation, the HB1, is the cornerstone of this legend.

Before Bimota: a brilliant engine, a fallible frame

The Honda CB 750 was a mechanical star for its time. Its engine was a jewel of technology. Unfortunately, its double-cradle steel frame, though sufficient for standard use, quickly showed its limits in sporty riding. Lack of rigidity, high weight and a less-than-aggressive geometry made it blurred and inaccurate at high speeds.

It was a frustration personally felt by a certain Massimo Tamburini, one of the three founders of Bimota (along with Valerio Bianchiand Giuseppe Morri). A motorcycle enthusiast and racer in his spare time, Tamburini was convinced that he could design a part-cycle capable not only of mastering the potato of the Japanese engine, but of transcending it.

After : The art of the chassis

The HB1, whose name simply stands for Honda Bimota 1, was his answer. Rather than modify the existing frame, Tamburini started from scratch.

The technical strength of the HB1 was its tubular trellis frame, made from chrome-molybdenum (CrMo) steel. This design offered far greater torsional rigidity than the original frame, while being spectacularly lighter. The Bimota frame alone weighed around 9 kg, almost half the weight of its Honda counterpart.

This obsession with lightness and rigidity was the common thread running through the entire project. The swingarm was also a custom-built, stiffer part. Other components, such as the sculpted fuel tank and single-seater seat shell, were made of fiberglass. The design was clean, functional and undeniably Italian, inspired directly by Grand Prix machines.

Before being a motorcycle, a conversion kit

Originally, the Bimota HB1 was not sold as a complete motorcycle. It was a high-end conversion kit for CB 750 owners. The customer supplied his "donor" motorcycle, and the Bimota kit included:

• Chrome-moly frame
• Swingarm
• Fiberglass tank
• Single-seat saddle and shell
• Recessed controls
• Wrist handlebars

The owner had to transplant his Honda's engine, fork, wheels, brakes and electrical system. The end result was a transformed machine. Tens of kilos lighter, lower, with an optimized center of gravity and more aggressive steering geometry, the HB1 could be ridden like a real road bike. It offered precision and cornering stability that the standard CB 750 could only dream of.

Rare from the start

Only 10 HB1 kits and one complete prototype were produced between 1972 and 1973. This extremely limited production makes it one of the rarest and most sought-after Bimotas in the world today.

But its importance far exceeds its rarity. The HB1 established the philosophy that would define Bimota for decades to come: take the best production engines available (mainly Japanese at first) and build them a showcase of Italian engineering and design. It was striking proof that the genius of a motorcycle lies not only in its engine, but in the perfect harmony of all its components.

M.Bi. - Photos D.R.