The First Honda Build Big Bike that Changed History

Do you know what inspired Soichiro Honda to commission the company's first big bike? According to some historians, on a trip to the US 'he noticed that American riders of very large build dwarf even machines of 650cc. On his return to Japan, Soichiro Honda initiated a development program for what became known at Honda as the 'King of Motorcycles'.

Few motorcycles can lay claim to having changed motorcycling history but the Honda CB750 is most certainly one.

It's said that Yoshirou Harada, the man who had been responsible for the ground-breaking CB72 and CB450 and who was put in charge of this project, on the guidelines he was given.
  • A highway cruising speed of between 135 and 160km/h. A broad engine power band with minimum vibration and engine noise. A high degree of safety.
  • Excellent stability, even when traveling at over 160km/h.
  • Strong and reliable braking, effective at high speed and with full loading.
  • Ergonomic riding position and controls, for a relaxed and comfortable ride.
  • Lighting and instrumentation which is patently sophisticated and reliable. Overall looks that will get the machine noticed by other road users.
  • Utter reliability from every component, while inspection and maintenance must be easy.
  • Full use of new materials, technologies and the latest surface treatments to ensure unique design and promote ease of production.
It seems that Harada's team took maximum advantage of the experience that Honda had gathered during its 1961 to 1967 GP campaigns, as well as the equipment bought for racing development. In the late '60s, Honda's engineers were already using computers when most other motorcycle designers were still sitting down at drawing boards in the morning.

Parallel twins vibrated too much, so the designers looked at V-twin and even horizontally opposed twins before the decision to build an inline four was made in February of 1968, apparently after encouragement from the Americans. The engine did not get the double overhead camshafts Honda was using on race bikes because they weren't necessary to achieve the power output required, but a lot of other and often quite unobtrusive race technology went into the design. And Harada was already making plans to introduce a DOHC engine two or three years down the line.

The design process was fast but it didn't all go smoothly, especially when the boss, who was generally distracted by the development of the eventually doomed 1300cc car, took an interest. The oil filter, for example, was originally housed in the clutch casing. When Soichiro Honda asked one of the engineers to show him how easy it was to change, it came out covered in grease. Honda was annoyed he apparently belted the unfortunate engineer across the head.

Amazingly, the Honda CB750 Four made its debut at the Tokyo Show in October of 1968, less than nine months after the engine style had been locked in. It hit the streets six months later.Tag: Honda Soichiro Honda Big-Bike 650cc CB750 Yoshirou Harada CB72 CB450 DOHC Tokyo Motor Show Production Manufacturer Engineer Technology Inline-Four Classic
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