Having captured five consecutive championship titles in the historic 1966 World Grand Prix Road Racing Series, Honda decided to withdraw from the World GP circuit beginning the very next season. Upon that announcement, the company turned toward its primary target: the development of high performance consumer machines. Thus it would achieve through the application of technology obtained in road racing.
Honda was in those days exporting more than half of its Japanese-made motorcycles. The company, however, did not offer large-displacement sports bikes, even though they were in great demand in developed countries such as the U.S. Moreover, sales of Honda motorcycles in America had begun to drop in 1966. Accordingly, American Honda had been asking for the development of new products.
The Dream CB450 was released in 1965 as a high-performance bike. Featuring a two-cylinder DOHC engine, it had been created at the request of American Honda, which wanted a higher-class version of its predecessor, the 305 cc CB77.
The CB450 sold relatively well, but it did not win acceptance as a major product. The majority of American riders, it seemed, did not judge motorcycles simply by how fast they could go. They also wanted responsive torque performance so that they could get the power they needed without downshifting. For many local riders, motorcycles represented a means of recreation and relaxation rather than rocket-sled performance.
Engine displacement of 650 cc was the largest to be found in Japan, yet these bikes accounted for only a few percentage points in the overall market. Harada therefore decided to develop a bigger model, as an obvious nod to the U.S. market. However, the request given by American Honda'"the bigger the better,"seemed quite vague to him. Based on that advice alone, it would be difficult for Harada to determine the right displacement.
It was then that (project development head Yoshiro)Harada learned from a reliable source that Britain's Triumph was developing a high-performance model with a 3-cylinder 750 cc engine. This bit of news determined the engine specification. By October 1967, the outline for Honda's new larger cc model had been defined: it would be driven by a 750 cc engine having a maximum output of 67 horsepower (one more than Harley-Davidson's 1300 cc unit, whose maximum output was 66 horsepower).
A team of about twenty members was assembled on behalf of the development project in February 1968. The design of the CB750 FOUR had officially begun. However, Honda was already the industry's leading producer of motorcycles, thanks to the popularity of its classic Super Cub. By introducing the CB750 FOUR, the company planned to become the world's top manufacturer in terms of quality as well as volume. This model's competition, however, would be formidable, since the pack included comparable models from Triumph, BMW, and Harley. Therefore, the new Honda would have to offer a superior level of performance and reliability in order to lead the field.
The objective of Honda's basic development plan was to make long-range, high-speed touring safer and more comfortable, while achieving superior output. Therefore, the emerging science of human engineering-called "ergonomics"-was to be incorporated structurally, right down to the finest detail. To facilitate the collaborative process among design engineers and production personnel, common engineering targets were established for product development. These included the following:
 Ensure stability during high-speed cruising (between 140 and 160 km/h) on highways, yet retain an ample margin of output for effective maneuvering in traffic.  Provide a braking system that is reliable and resis tant to high loads by anticipating frequent rapid decelerations from high speeds.  Minimize vibration and noise in order to reduce rider fatigue during long-range cruising. Provide an ideal riding position for comfort and the proper operation of controls based on human-engineering principles, and design the mechanisms so that the rider can easily learn how to operate them.  Ensure that various ancillary devices, such as lights and instruments, are large and reliable. They must be designed to help the rider make sound judgments and ensure sufficient visibility for surrounding vehicles.  Extend the service life for each device and ensure that it provides for easy maintenance and servicing  Create original designs that also are easy to mass produce by utilizing newer, better materials and production technologies. This applies particularly to cutting-edge surface-treatment technologies.
Fortunately, Harada had come across some after-market disc brakes in a motorcycle accessory outlet during his trip to the U.S., and they had proved effective in the CB450. As a result, he immediately visited Lockhart, the developer and manufacturer. After consulting with the supplier's staff regarding the ideal design, Harada left the company with a set of their products. He secretly believed the new model they were going to develop might offer an opportunity to adopt disc brakes.
The day of the 1966 Tokyo Motor Show, scheduled for October, was fast approaching. However, Harada was still unable to make up his mind. Therefore, he brought two different brake specifications to Soichiro Honda and asked for some advice.
"We've designed two separate specifications having different braking systems," he told Mr. Honda. "One uses conventional drum brakes and the other had disc brakes. Of the two, the disc-brake specification had only recently been developed, so it will need more tests. If disc brakes are adopted, we aren't sure we can meet next spring's completion target."
Mr. Honda's reply, though, was simple and direct: "Well, of course we'll have to go with disc brakes."
The CB750 FOUR was a hit at the Tokyo Motor Show, flashing its big disc brakes to throngs of admirers. Rave reviews began pouring in.
The CB750 FOUR was released in the U.S. in January 1969. That year, Honda held its first U.S. dealer meeting in Las Vegas, Nevada, a gathering of motorcycle dealers from across North America. The meeting's objective was to motivate sales, which had been sluggish since 1966. As a strategic move prior to the coming spring season, the meeting was also attended by company representatives from Japan, including Soichiro Honda himself. The event's true highlight was the introduction of the CB750 FOUR and other new models such as the Z50 and SL350.
"A retail price of $1,495 was announced by American Honda's President Kihachiro Kawashima at the Vegas meeting," Harada remembered. "Since large bikes were selling for between $2,800 and $4,000 in the U.S. at that time, all 2,000 dealers burst into thunderous applause when they heard its price. I've even heard that the machine fetched a premium as soon as it was on the market, selling for $1,800 to $2,000."
Honda's previous models used a spilt-type, press-fit crankshaft having a needle bearing. However, the four-cylinder powerplant in the CB750 FOUR employed an integrated crankshaft and metal bearing. At Saitama Factory, the staff wracked their brains trying to identify the right machining equipment and line configuration to produce a part they had no experience making. They even visited automobile manufacturers in order to acquire some knowledge they could use to plan the line.
Efficiency on the line was poor initially, and as a result the production volume was at most five units per day. However, the machine became an instant smash hit, bringing tears of joy to everyone involved with the CB750's creation. The initial production forecast of 25 units per day was pushed up to over 100 units. Back orders piled up as a result of this explosive, yet completely unexpected sales activity. Soon, the production of sand-molded crankcases, for which the factory did not have a dedicated machine, could no longer meet the rate required for mass production. In response, the entire crankcase production facility was upgraded to adopt the metal die-cast type. The line was gradually enhanced as production volume increased. However, every time the volume was adjusted, additional employees would be mobilized to run a temporary line. Everything had to be accelerated in order to produce such a number of bikes at Honda's level of quality. Ultimately, though, the production of engines and bodies was transferred to Suzuka Factory-in July and October 1971, respectively-as part of the company's endeavor to satisfy customer demand.
Honda had succeeded again, bringing other Japanese manufacturers into the arena with sports bikes featuring large, 750-cc engines. Therefore, it is no exaggeration to state that the Honda CB750 FOUR was a pioneer model in that regard. In fact, it gave birth to a new category known in Japan as "Nanahan."(750 in Japanese) Yet the Honda model, with its decidedly high-performance intentions, also fared very well on the racing circuit.
The in-house racing team at Honda R&D brought their CB750 Fours to compete in the Suzuka 10-Hour Endurance Race scheduled to be held in August 1969, soon after the model's commercial launch. Honda dominated the race with a one-two finish by Blue Helmet MSC. The team of Morio Sumiya and Tetsuya Hishiki took first place, while the pairing of Yoichi Oguma and Minoru Sato came in a close second.
Veteran rider Dick Mann, meanwhile, streaked to victory on his CB750 FOUR at the AMA Daytona 200-Mile Race in March 1970. It was a ride that sent customers throughout the States running to their Honda dealers. In reflecting their conviction that "bigger is better," American riders soon wanted a bigger bike with an engine offering even larger displacement.
The American hunger for large bikes was enhanced with the 1972 launch of Kawasaki's hot new 900 cc ZI. Forced to develop a more appealing sport bike with a larger engine, Honda launched its 999 cc Gold Wing GL1000 in the American market. The units were initially exported from Japan, but as demand grew production switched to Honda of America Manufacturing (HAM). In May 1980, the first U.S.-made GL1100 machine rolled off the line. It was very well received in the U.S., becoming a major force in the growth of local production activities.