CB: The Big Bike Origin and Ideal
The Dream CB750 FOUR, launched in 1969, was equipped with a modern air-cooled 4-stroke 4-cylinder SOHC 2-valve engine with a displacement of 736 cc, and was completely locally produced at a time when no other manufacturer in the world had a mass-produced model with an in-line 4-cylinder engine. The imposing four mufflers that gave the impression of the multi-cylinder technology cultivated in the World Grand Prix and the hydraulic disc brake on the front, the first on a production model at the time, made it the first “big bike,” and its originality could be considered Honda’s next invention after the Super Cub.
With a maximum output of 67 PS, a 0-400 m time of 12.4 seconds, and a top speed of 200 km/h, the CB was one of the world’s top production motorcycles of its time. Even Soichiro Honda was surprised at first, saying, “Who would ride such a big bike?” However, riders everywhere were immediately attracted, and it quickly rose to the pinnacle of the world’s motorcycle scene.
Dream CB750 FOUR
Dream CB750 FOUR in Action
Stimulated by the CB, other manufacturers launched competing models, resulting in a fierce battle for market share. In the early 1970s, when Kawasaki Heavy Industries, Ltd. (Kawasaki) introduced the 900 Super Four (Z1) and the 750RS (Z2) for the domestic market, Honda responded with measures such as a renewed CB which was accepted in the U.S., but as it failed to win the hearts of Europeans, little by little, Honda’s position was being threatened. In 1977, Honda's share of the European market was in crisis, and as part of the recovery effort, Honda introduced the RCB1000 prototype motorcycle to the European endurance racing series, to overthrow the then champion Z1 in a series that was influential in the European market. From 1976 to 1978 the RCB had completely dominated the European series, and in 1979 had secured Honda’s fourth consecutive manufacturers’ and riders’ titles.
In 1979, a new generation of CBs reflecting the technology and image of the RCB was launched: the CB900F / 750F. At the same time, the DOHC 6-cylinder CBX1000, a new sports model with a beautiful DOHC 4-valve engine mounted in a sleekly “Integrated Streamline” styled body was also launched. Once launched, the CB900F / 750F were extremely popular in Japan, the U.S., and Europe, and the CB brand returned to the top of the world’s big bike market.
CB750F
CB750F in Action
The CB had become synonymous with high-performance big bikes, but in the 1980s, the pursuit of technical performance shifted to models with V4 engines. From 1982 to 1991, Honda’s lineup of large sport models consisted of the V4 and the CBR supersport models, and there was no big bike to make a strong CB impression.
“At the time, when I listened to my junior colleagues discussing motorcycles, they were always talking about reimported straight-4 (in-line four-cylinder) models from other companies, and it angered me, because my experiences were with the CB750 FOUR, CBX1000, and CB1100R, in-line engine models that made me feel proud of Honda and Japan. This frustration led us to launch Project BIG-1,” said Toshiaki Kishi, designer of the CB1000 SUPER FOUR (SF) (called BIG-1 at the time).
Project BIG-1 began with rough sketches that Kishi drew of a CB-1 (400 cc) chassis with a large CB1100R fuel tank. Koji Nakano, who was in charge of design team at the time, saw it and began to talk about the possibility of creating a straight-4 big bike like it. At one point, Nakano was shocked to hear people say, “People think of Kawasaki when they think of big bikes. Honda has many models, but it seems to be a 250 or 400 company.”
“Despite the fact that the BIG-1 was an unofficial project, we began our studies with clay models in a prime location in the design office, so that many development associates would see it, aiming to build momentum within the company. As planned, the number our supporters gradually increased.” (Kishi)
As an advocate of the concept, Kunitaka Hara developed the concept with the team as Large Project Leader (LPL). He recalled:
“At the time, I also felt that there were no bikes for grownups to ride these days. So, when I saw the clay model Kishi had made, I thought, ‘This is big and powerful,’ and said to myself, ‘I like the way it looks so solid to ride.’ My original experience with large bikes was the CB750 FOUR (K0), and to me a straight-four model with an intimidating presence was what the CB was about. That’s why I wanted the BIG-1 to be a bike with ample torque and a dynamic ride. ”As a designer, Kishi insisted on 18-inch front and rear tires. Tire size was an important factor in determining the size of the bike, but at the time, there were not domestically produced 18-inch tires for large models, and there were considerable objections from within the team. Hara pushed ahead, saying, “Honda is a company that takes on any challenge.”
However, the BIG-1, which was proposed internally by the development team, was rejected from a sales point of view, as a model with conventional dual shock absorbers could not be expected to sell well in Europe and the United States. Hara decided to ask the users directly, and exhibited the BIG-1 at the Tokyo Motor Show as a reference model, to promote the image of the CB400SF, which was being developed at the same time.
CB1000 SUPER FOUR rough sketches
Clay model on display caught the eyes of development associates, and raised morale within the company.
CB1000 SUPER FOUR (First-generation BIG-1)
“The visitors were intrigued. The way everyone would look over every square inch of the bike reminded me of when the CB750 FOUR was exhibited at the 1968 Tokyo Motor Show.” (Hara)
As a result, the BIG-1 was launched in November 1992 as the CB1000 SUPER FOUR, and became a hit product, selling approximately 4,000 units in one year. Other companies saw this trend and released competing products. In 1996, deregulation made it possible to obtain a license for large motorcycles at riding schools, which provided a tailwind and triggered an unprecedented big bike boom in Japan.
Some users wanted bigger bikes than others, and in 1998, engine displacement was increased to 1300 cc. Output was increased from 93 PS to 100PS, and low and mid speed response was further enhanced. The chassis was modified for an easier ride, with 17-inch tires front and rear and a lowered seat height. Brakes and suspension were strengthened to match the increased displacement, and although performance was improved as intended, the bike’s weight increased from 260 kg to 273 kg.
CB1000 SUPER FOUR in Action
CB1300 SUPER FOUR (Second-generation BIG-1)
CB1300 SUPER FOUR (Second-generation BIG-1) in Action
Heavy it may be, the BIG-1, launched as the CB1300SF, sold 4,600 units in its first year, exceeding the sales plan and becoming the series’ biggest record in a single year. In 2003, a new model focused on weight reduction and the adoption of PGM-FI (electronically controlled fuel injection) was released, and since the third generation onwards, has undergone numerous modifications and has been refined until now, more than 30 years after its launch.
Even as market needs and regulations have changed over the years, the concept since the CB1000SF of improving ease of use and comfort remain unchanged. “A bike you want to ride and own.” This is the ideal big bike, in other words the CB, an ideal both the maker and the user share.
CB1300 SUPER FOUR (Third-generation BIG-1)
CB1300 SUPER FOUR (Third-generation BIG-1) in Action
CB1300 SUPER FOUR SP
Project BIG-1 30th anniversary model
CBR: The Ultimate “Joy of Riding”
The CBR900RR Fireblade made its stunning debut at EICMA in Milan in November 1991, at a time when the 750 cc Superbike regulations were soon to take effect in 1994, replacing the 1000 cc TT-F1 (Tourist Trophy Formula One) regulations. The concept of the new model was “Total Control,” to enjoy sports riding to the fullest.
First-generation CBR900RR
CBR900RR (First-generation) in Action
“We wanted our customers to enjoy riding to the fullest. We also wanted to avoid surprises for the rider. There are situations on winding roads or in the city that the rider is surprised, but we wanted a bike that the rider could control to the fullest to avoid these situations. I felt that if we designed such a bike ourselves, and could enjoy it ourselves, we could offer it as a product that would satisfy our customers,” said Tadao Baba, then LPL. Baba, who had been a test rider for 30 years, was selected as LPL because of his experience. (He was LPL up to the sixth generation in 2002.)
Baba set the goal of achieving a dry weight of 185 kg and wet weight of 200 kg or less to make sports riding fun and to provide handling that the rider can control at will. Based on this goal, Baba sought a lightweight chassis equivalent to a 600 cc model with a power output comparable to a 1000 cc model, setting the optimum balance 900 cc. While most sports models at the time commonly used maximum output and maximum speed figures as the basis for their product appeal, the Fireblade was judged to have sufficient performance with a maximum output of 125 PS and a maximum speed of around 260 km/h, and Baba focused on making it lighter.
An increase in displacement would normally lead to an increase in weight, and achieving 185 kg for a 1000 cc model would have been difficult with the technology of the time. Weight reduction in the development of the Fireblade was carried out on a gram-level throughout its entire chassis. Hirofumi Fukunaga, chassis design project leader (PL) at the time (who succeeded Baba as the LPL of Fireblade in 2004), said:
“The first thing Baba told me was to manage even the weight of the graphic stripe decals. At first, I was surprised and impressed, but it was only because we went that far that we were able to meet our goals, and we would not have been able to do what we did otherwise. Weight cannot be reduced in a single swoop, so it was important to see how many ideas we could all bring to the table.”
One reference for understanding the characteristics of the first-generation Fireblade would be to compare its specifications with the 600 cc + 4-cylinder models that Honda was selling at the time. Below is the 1992 model’s maximum output, dry weight, and wheelbase. Although 125 PS maximum output for a 900 cc model seemed reasonable, it was far less than the CBR1000F, another full-fairing model, and its dry weight and wheelbase, similar to the CBR600F, would have been impossible for a conventional 750 cc + 4-cylinder model. These were impossible figures.
The all-new inline 4-cylinder engine introduced a side cam chain and an upper crankcase integrated with the cylinder in order to achieve a compact and lightweight design. To overcome the gear train’s weight and size disadvantages, a chain-drive camshaft was used, as well as positioning the ACG (alternator) on the left edge (rather than the more conventional rear) of the crankshaft to reduce the number of components.
CBR900RR : As powerful as a 1000 cc bike, yet as light as a 600 cc bike
A lighter, more compact inline 4-cylinder engine
The first generation Fireblade also introduced revolutionary mechanisms throughout its chassis. The frame was an aluminum twin-spar frame, the standard for super sports models, but the extruded main tube had a unique shape with an irregular cross section and a four-layer structure, which was extremely difficult to create. The positional relationship between the transmission output shaft and swingarm pivot was carefully tested in search of the ideal anti-squat (preventing the rear from sinking under acceleration) characteristics. The numerous holes drilled in the fairing made handling lighter and reduced weight, a technique learned from the RVF750 factory bike.
Revolutionary combination of telescopic front forks with 16-inch tires
What had an even greater impact on performance was the 16-inch front wheel and telescopic front forks. At the time, 17-inch front wheels were already becoming the standard, but the unprecedented combination of a short wheelbase and high power output required a front wheel width of 130 mm, as the front wheel could not provide sufficient ground contact. However, a 130/70ZR17 tire would have a bigger outside diameter, and 130/60ZR17 would make the ride less comfortable. An unorthodox 130/60ZR16 was adopted to increase the width while maintaining the same outer diameter as that of 120/70ZR17.
The adoption of a telescopic front fork was to avoid weight increase for steering, and at the same time to ensure freedom of fork pitch, which affects ride quality. In addition, to achieve rigidity equivalent to an inverted fork, a 45 mm diameter inner tube was chosen, which was extremely thick at the time, and a two-piece forged aluminum base structure was adopted, resulting in a weight reduction of 700 to 800 g per fork.
Thus, the innovative and exceptional first generation Fireblade gained popularity with many riders around the world, especially experienced riders. Still rough and edgy in places, subsequent Fireblade models were improved to make handling easier while maintaining high performance, and the later third-generation model, which appeared in 1998, matured to the level the development team had envisaged.
From 2000 onward, the Fireblade evolved boldly with each successive generation in response to the changing times and the rise of rival manufacturers. In 2004, displacement was expanded to 1000 cc as a race homologation model, and MotoGP technology was also introduced. 2020 saw the introduction of the 1000RR-R, with a maximum output of 218 PS, which was designed for track use. The Fireblade nonetheless kept true to its original “Total Control” concept, which remains unchanged over its 30 years of history.
CBR1000RR-R Fireblade SP 30th Anniversary model
