Universal Japanese Motorcycle

The basic platform was an upright, open seating position motorcycle powered by a carbureted, air-cooled engine wrapped in a steel-tube cradle-type frame, and at least one disc brake to bring it all to a stop. The simple design made motorcycling accessible to riders of all types and skill sets. UJMs were available in various displacements, and their ubiquity helped grow motorcycling in America during the 1970s and ‘80s.

The term "Universal Japanese Motorcycle", or UJM, is a term coined in the mid-1970s by Cycle Magazine to describe a proliferation of similar Japanese standard motorcycles that became commonplace following Honda's 1969 introduction of its successful CB750. The CB750 became a rough template for subsequent designs from all three of the other major Japanese motorcycle manufacturers. In 2011, the New York Times said lightning struck for Honda "with the 1969 CB 750, whose use of an inline 4-cylinder engine came to define the Universal Japanese Motorcycle."

The UJM template featured a four-cylinder engine, standard riding position, carburetor for each cylinder, unit construction engine, disc front brake, conventional tubular cradle frame and telescopic front forks and twin-shock rear suspension. As the major Japanese motorcycle manufacturers, Honda, Kawasaki, Suzuki, and Yamaha, began replicating each other's designs, the UJM's created a homogeneity of form, function and quality. UJMs included such prominent models as the Honda CB500, the Kawasaki Z1, and the Suzuki GS750. Such machines had massive sales, and UJMs continued to be produced for more than a decade, with some examples like the CB750 Nighthawk continuing into 2003.

In 1976, Cycle described the new phenomenon, saying:

In the 2010 book, Sport Bikes, Hans Hetrick wrote that "throughout the 1970s, the Japanese companies experimented with different types of engines and frame designs. Their ideas soon came together in a rock-solid package. This design became known as the Universal Japanese Motorcycle, or UJM."

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