In 1992, Honda launched the CBR900RR, making a step change from the engine power and displacement supremacism that dominated the super sport bikes scene, and allowing every rider to enjoy total control. Believing that customers would shy away from a bike that was neither 750cc nor 1,000cc, Honda affiliates in Europe first sold the new model as the “FireBlade” without a displacement figure. In time, however, even Europe embraced the name “CBR900RR,” signaling that a new way of understanding and valuing super sport bikes was spreading across the globe. In 2000, the fifth-generation CBR900RR (CBR929RR) further refined the vision of the first-generation model. Virtually all of its structural elements reflected a new and advanced technological approach, including its new higher-displacement engine, which was the first in the series to incorporate a fuel injection system.
Former Honda Racing Corporation (HRC) works rider Hikaru Miyagi: The first-generation CBR900RR really rocked the world with its lightweight and compact design. Yet, in subsequent model changes over the years, it got even more powerful and lightweight.
Seventh-generation CBR1000RR development team leader Hirofumi Fukunaga: In the third generation, we made the exhaust pipe stainless steel and eliminated the fuel pump, reducing weight by 1 kg. In the fourth generation, we redesigned 80 percent of the parts and reduced weight by approximately 3 kg. When competing bikes reached the market, we considered raising displacement to 1,000cc, but with our technology at the time we would have ended up increasing weight by about 10 kg. We felt that the merits of raising output were not worth the demerits.
Miyagi: What was the concept of the fifth generation, which was a full model change?
Fifth-generation CBR900RR (CBR929RR) body design team member Toshihisa Nagashii: The concept was still the same: letting riders enjoy total control. Our approach to realizing this concept was to make the bike even more lightweight and compact, step by step, carefully and thoroughly. This approach was same as for the first generation model, when we had the goal of creating a motorcycle that could beat the RVF750 in the Suzuka 8 Hours Endurance Road Race. I was responsible for calculating the weight of the parts, and I found that, when the motorcycle was assembled, it weighed 500 g more than the weight of the individual parts. When I reported this fact to LPL [Large Project Leader = leader of model development] Baba, he got quite angry. When I replied, “But that’s just 0.5 percent of the total weight,” he said, “Well, that 0.5 percent is important!” That’s how crucial weight was in this project.
Miyagi: In terms of the human body, that’s about the weight difference one would expect after drinking a cup of coffee. Perhaps even a single decal on the bike could create such a difference.
Ninth-generation CBR1000RR designer Toshiaki Kishi: Right. Instead of using a layered two-tone color scheme and a lot of decals, which would have increased weight, we took on the challenge of realizing the Honda tricolor color scheme on the bike.
Miyagi: For a commercially produced motorcycle, that’s incredible!
Nagashii: The 2000 model and the following 2002 model had a hinge on the rear seat whose weight we were working to reduce gram by gram. It was the kind of weight that we couldn’t ignore when other team members were struggling with a single decal. So I suggested to LPL Baba that we simply not use the seat hinge, but he got angry with me and said, “You don’t get it. That hinge is part of the identity of this model.” [Laughs.] I wondered what he meant, but one time LPL Baba and I went touring on CBR900RR bikes, and I put a rain poncho in the rear seat compartment. While we were touring, I almost unconsciously put things into and took things out of this compartment, and when I suddenly became conscious of it, I realized how convenient the hinge made it to open and close. It was just a small thing, but it symbolized the fact that the road is the true home of a super sport bike.
Not only by making such bold moves as using lightweight titanium in the muffler and part of the exhaust pipe but also by painstakingly reducing the weight of parts gram by gram, the development team created a fifth-generation CBR900RR (CBR929RR) that weighed about 15 kg less than the first-generation machine. Two years later, the 2002 model weighed an additional 2 kg less. Yet making the motorcycle lightweight on the spec sheet alone was not enough to satisfy the team.
Miyagi: One of the main features of the fifth-generation model is the pivotless frame, in which the swingarm is separated from the main frame. What was your purpose in introducing this new structure?
Fifth-generation CBR900RR (CBR929RR) Assistant LPL Kenji Hasegawa: As the years went by, the power of the model kept going up, and we had to increase stability accordingly. This meant increasing the rigidity of the frame. In a race, that’s fine, but on the street, too much rigidity can make a bike difficult to ride. Vehicle behavior can get a bit oversensitive.
Miyagi: That’s true.
Hasegawa: So we adopted another method of increasing stability, which was to attach the swingarm to a pivot on the crankcase instead of to the frame, making the frame itself pivotless. This structure gave the rear the right amount of freedom of movement while enhancing stability. Without making rigidity too high, this structure helps provide the handling stability a super sport bike requires, as well as a light riding feel that makes the bike seem even lighter than it is. We took on the challenge of creating this structure for the fifth generation, and I think it was perfected in the sixth generation with the 2002 model.
Miyagi: I see. The performance of the model kept going up over the years, and since the street was where riders would mainly experience this performance, the pivotless frame was a new way for you to further refine the model as a street bike.