The CM450A was a motorcycle

Motorcycle

A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

 made by Honda

Honda

is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...

 in 1982 and 1983. It was based on the CB400

Honda CB400

The Honda CB400 Super Four is a continuation of the Honda CB400 four. It is an all-rounder bike, sporty and suitable for learner riders where the low weight and ease of handling can help build riding confidence and ability. ABS brakes are an option on later models...

 and CM400

Honda CM400

The Honda CM series was a street bike precursor to the Honda Rebel series of motorcycles produced from 1979-1981. These bikes had a 395cc parallel twin engine that was air-cooled...

 models (1978-1981), especially the CM400A Hondamatic (1980-1981). It had a 447cc SOHC parallel twin engine with two carburettors and a 2-speed transmission with a torque converter

Torque converter

In modern usage, a torque converter is generally a type of hydrodynamic fluid coupling that is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating driven load...

. It was not a full automatic, however, because the rider had to manually shift between low and high. It is called automatic because there is no clutch required due to the torque converter, and shared the Hondamatic

Hondamatic

The Hondamatic was Honda's first automatic transmission. It was produced from 1973 through 1979. The Hondamatic name is used on all automatic transmissions from Honda....

 trade name with Honda cars that had true automatic transmissions.