1. Aiming for specs to win a race

• Please tell me how the development started.

Ishikawa: While races were growing strong as the Asian Road Race Championship (ARRC) did, Honda had started losing its competitive power more and more back then. During a discussion on what Honda could do to boost it, the objective was set at developing the CBR600RR to win races in Asia. To win races was the start point.

Koyama: I heard that Honda was going to develop the 600 to win the ARRC and was asked to be a development rider. As it was my first time to be involved deeply with motorcycle development, I was very much looking forward to it.

Ishikawa: At that time, Mr. Koyama competed in the ARRC. I went to Thailand to watch the championship and felt frustrated. In the talk with Mr. Koyama, we agreed on the direction to aim at. I felt that with him we could build something good, so we requested his participation in the development.

• So, that is how you worked out the concepts.

Ishikawa: Since the development was launched to pull off a victory in a race, the concept of “specifications to win” is no surprise. Also, the 600 class is, how should I put it, the size easier even for us to ride around. I believe it is the best super sportbike class to have fun with. I myself have had fun on this motorcycle and enjoyed the joy of maneuvering a super sportbike. Thus, I would like to keep such a joy alive so that customers can feel the joy of maneuvering it at the higher level. This is our continued aspiration. Furthermore, even while its performance was boiled down to serve as a race machine, we didn’t want to let original appeals of the CBR600RR go: that it comes in the optimum balance and is easy for anyone to handle. We wanted them to advance. That is how “Stress-free Total Control” became the second concept.

Doyama: I was a project leader (PL) for the control systems of the RC213V-S debuted in 2015. The development triggered a rapid advance of Honda’s electronic devices. The engine drivability had become so much better at that time that I was fascinated to see such an exciting engine. I was thinking it would make the 600 model the best motorcycle if it was built with this feel when the development of the CBR600RR came up. As I was involved in the ARRC, I came forward to join the development to end up as an assistant large project leader (ALPL).

2. Engine infused with 14 years of aspirations

• What sort of development did the engine team do?

Shigematsu: We set a target value and checked through tests if the targeted horsepower could actually be attained. What was the most distinctive in this development was the development sequence. Normally, a race development follows completion of a certain stage of a mass production development. However, this time, because we definitely wanted victories in races, specifications were defined on a race machine at the stage of prototypes before moving on to the mass production development.  In retrospect, I feel that this kind of approach was critical to accomplish the targeted horsepower. 

3. Designing a frame to win a race

• What about the frame team?

Wakamatsu: The frame was in the same situation. We went to watch the ARRC to begin understanding our motorcycle was less competitive especially in the decelerating section. So, we requested racers to test directions of settings we were thinking about. As many of them were young, results were sluggish. But they got used to the setting little by little to win in 2020.

• While looking at the race trends…

Wakamatsu: Deceleration was stabilized with front components in the development testing on the race track. Aside from that, as we were in need of improving some difficult areas of throttle control, we studied a change in swing arm length. Swing arm length can change only by an increment of 16 millimeters due to the chain link. So, we looked into extending the length to the rear axle by 3 millimeters, and confirmed with designers of components around wheels that extension would allow the targeted rear axle position setting, even when gear ratios on different race tracks were taken into account. The swing arm was extended by 3 millimeters. For better stability, we added 15 millimeters to the entire length of the front fork to give more freedom to the vehicle posture. 

• That was how to secure stability during braking and when the throttle opens up.

Wakamatsu: Yes. This design stabilizes the vehicle during activation of the brakes and facilitates the throttle to open. The winglet was also a factor to make it happen, through stabilizing front grip pressure to draw corning force. Owing to this cornering force, the machine longer in total length can race and score record times coupled with the previously mentioned engine performance.

Koyama: The key to run fast is how to shorten the braking distance and how fast to release the brakes for gathering the cornering speed. By making the entire length of the front fork longer, the front protrusion becomes less for higher front setting. The rear will not be lifted up and braking is stabilized even if I grip the brakes tightly. It’s simple enough when I release the brakes fast and the front gets lifted up, the machine swerves toward the outside of the corner. There comes the winglet doing its job to bring me back on the line I envisioned to turn the corner. I think the motorcycle has merged the best of the two at a high level. When it comes to smaller details, while testing and modifying various items like rear axle tightening torque, we made on-the-spot changes small to others but sometimes major for a rider in terms of feeling. If I remember correctly, after the swing arm was replaced with a longer one, a simple change of a rear axle collar to a more rigid one drastically improved time on a second-by-second basis, correct?

4. 600cc, the best package to savor the joy of maneuvering

• Is the size of the 600 easier to handle by and large?

Ishikawa: You don’t feel it lacks power, but it certainly doesn’t produce outrageous horsepower you cannot handle. It’s not that heavy, and it comes in a suitable size in the sense that a person rides it. What is fun about riding a sportbike is that we can maneuver it at will. In that sense, I think this 600 is in the right size.

• Do you agree, Mr. Doyama?

Doyama: Just as he says. It is good-sized and the throttle can be controlled appropriately. The engine outputs power not excessively in the low range but it revolves comfortably once the rpm reaches the high range. On top of that, this frame packaging, the size distinctive to a 600cc motorcycle and the engine feel are reasons for easy handling.

Koyama: For me, a 1000cc motorcycle is hefty to manage because of its engine power and large heavy body. A 600cc is great for smaller men and even women for a fun ride.

• Is there any change in the riding position?

Wakamatsu: The riding position for the mass production model stays unchanged from the previous one. As it is not a hard-core race machine but is a sporty one, we believe this is handy mass production motorcycle for rides in a variety of situations. The fuel tank shelter geometry was our elaborate outcome from test rides with Mr. Koyama. Not only it was trimmed down, it is shaped to be held better in arms or thighs while turning the corners.

• The new feature is a winglet.

Koyano: My main responsibilities included windproof performance, protection, running resistance, traction control, wheelie control, etc. Among them, I experienced difficulties the most with the winglet. The challenge of my team was how to minimize running resistance in order to hit the maximum speed. Because the winglet inevitably increased the frontal projected area, we focused our attention on a rider. We added concavity to the tank, lowered the rider’s head position and stood the screen up so as to keep the rider from getting gusts as much as possible to reduce the entire running resistance. In contrast, the winglet is a part that stabilizes front tire grip pressure during turns in corners in the first place. So, not only resistance needs to be lowered, steering stability had to be enhanced. However, steering stability and running resistance are in a conflicting relationship: when the former one is enhanced, the latter one increases. Nishiyama and I confined ourselves in the wind tunnel to seek a balance between steering stability and running resistance at a higher dimension by trying different winglet profiles, locations, angles, etc.

Koyama: Windproof performance is totally a different matter. When I rode previous models on the straight racing track, my neck got tired and my head was sometimes swayed by wind even with my head lowered. Wind noises are so loud that I don’t hear engine sounds. On the contrary, this new model protects my entire body including my shoulders behind the screen, my head does not get pushed around. It was tough before even on a straight track, but I can rest on the new model while running on a straight track. It makes a big difference.

5. Equipped with the same control systems as “the” RC213V-S

• Is it the control system that prompts maneuverability?

Doyama: As I mentioned earlier, the RC213V-S was developed under the concept that the genuine RC213V would be mass produced as is. For this reason, some may think that the RC213V-S would be difficult to ride or it would be meant only for the MotoGP participants. But actually that machine is for everyone and very easy to handle. With the RC213V-S, we wanted everyone to know that a motorcycle had to be easy to ride otherwise it wouldn’t go that fast. And we thought, if equipped with the electronic devices for the RC213V-S, the CBR600RR would be invincible. Accordingly, we stuffed the CBR600RR with all of Honda’s advanced devices existing at present. It is just the same as the RC213V-S. It would be a wasted opportunity not to try this motorcycle to see how easy it is to ride.

Ishikawa: It has everything we could add as features. The model has been built with a power selector, traction control, wheelie control, engine brake control, assist slipper clutch, etc. IMU to detect the vehicle posture is utilized to the ABS and Honda Selectable Torque Control for better vehicle stability. A quick shifter is offered as an option.

Doyama: It is a real good deal. How about one for you? (laughs)

• Did Mr. Koyama feel the ease of handling during testing?

Koyama: It was beyond my expectations. To tell you the truth, I had thought features like traction control and wheelie control unnecessary. If it had been a 1000cc-motorcycle, a power mode would have been a plus. In fact, I rode a 600 with no special features added at all but with no problem. But I could significantly perceive the control once I actually activated the systems. It is true that the throttle bursts open when output is turned down with the power mode, but I felt it sometimes short in an actual race. Indeed, the feeling of exiting the corner with a tight grip was quite exhilarating. After that, switching to the full power mode, the machine exerted great power and speed, making me feel that I could score an excellent time. But actually, the more I turned down the power mode, I could set the same time with no pain. When I pop open the throttle intentionally in a rough manner from way before, the motorcycle turns the corner easily and beautifully. If I set at the full power mode, I had to control the machine myself. But sometimes I became impatient to run fast, ending up with opening the throttle so fast that the machine slipped.   Or because of some small behavior, the bike didn’t change its orientation. When the control was activated for such occasions, the motorcycle changed its orientation neatly or exited the corner in a clean way even if the throttle was opened earlier. I realized it made the ride easier. I tell you honestly. Even with the 600, the ride will be more fun with all the control systems equipped.

• That is what you meant when you said earlier, “The electronic control system was also very helpful.”

Koyama: The motorcycle was really easy to ride. Two days before the test at Sugo, I was in a race in rainy Okayama. I was on my own race machine of this year at that time. Two days later at Sugo, when I tested the new CBR600RR in the rain mode, it was really easy to ride. I was really impressed by the control. Even without paying attention to small details, the machine doesn’t show any strange behaviors. I didn’t experience incidents like a failed orientation change due to unexpectedly excessive opening of the throttle, or unsuccessful tire grip. The tire spontaneously gripped and the bike changed its orientation without effort, letting me concentrate on other things while running.

• You don’t have to wrestle with the bike. 

Koyama: I could use my attention on some other areas to see what I should do to run faster. In comparison, I was greatly bewildered when I got back to my own race machine for this year.

• Impressive control systems.

Akiyoshi: I am honored to hear such words from a rider like Mr. Koyama. What a rider can do to a motorcycle on a run is to turn the throttle. It is not in the case of applying brakes but accelerating. Motorcycle postures are detected to interpret an acceleration status to make the machine behave as close as possible to the way the rider intends. We create programs for such behaviors the motorcycle should show when the throttle opens in such a way in such a situation, etc. The electronic control systems interpret according to the program, read the rider’s intentions to control power, and so on, to create easier conditions of the motorcycle to ride.  Every one of our team tested various running situations and adjusted settings here and there to finally complete this control system package.

• The control systems are easier to implement because the original characteristics of the model are good.

Akiyoshi: Of course, that is also the case. But even so, deviations occur. For example, when one traces a circle with watercolor paint from high up, the line inevitably goes off the circle. An electronic control device corrects and removed what went off. That’s what an electronic control device is. When you get a bit clumsy and your line goes off to the side, the device removes the imperfection a little bit. With human intention untouched, a control system pulls the behavior back to where it should be when it goes too far. Normally this is a one-to-one operation between the rider and the machine. The electronic control system intervenes as a translator to make the behavior as close as possible to that intended by the rider. This is our aim of development.

• Where there is an intention, there is support to make sure the intention becomes reality.

Akiyoshi: Riders are not always professionals like Mr. Koyama. There are regular users like me who are not trained very well and they get unavoidably clumsy.  When that happens, the control system restrains the motorcycle so that a regular rider feels it a lot easier to handle. The system is also designed to protect the rider up to a certain degree. Of course, it will not be able to do so if the behavior goes beyond the limit too much. The system is a means to assist a rider to make a reality of what he or she wants to do. There are humans, and the system is there to gently support them. That is the concept of Honda’s electronic control systems. Humans come first in every respect.

• Mr. Doyama, Mr. Koyano, and Mr. Nishiyama actually rode the model for the development. Please tell us the ease of handling more specifically.

Koyano: As I own a CBR600RR, the version before the electronic control systems were added on, I very well notice the progress. In addition to the ease of handling and power, as I mentioned earlier, the traction control of my responsibility is a supporting feature for riders like Mr. Koyama who want to run fast, but not limited to that. There are as many as 9 modes, of which the lowest mode is programmed for saving a rider who may slip on a manhole on a rainy day. This motorcycle is also for those who have just received a license for a large-sized motorcycle. We aimed to save inexperienced riders who gave up on motorcycles after a single rollover and their cost of repair because it is not an inexpensive motorcycle.  I think improvement was made in such areas. During the development, I had a chilling experience in a reproduction test to slip on a manhole, but even so I will be delighted if customers are satisfied with the outcome.

• Is it the winglet which facilitates a corner turn?

Doyama: No doubt. Mr. Koyama tested with and without the winglet at Sugo. Probably he noticed it very well at that time. I was also amazed by the winglet’s effectiveness when I first tried it. It makes a world of difference. I now understand why an airplane has a wing.

• So the targeted “specs to win” and “joy of maneuvering” were satisfied.

Ishikawa: Yes, they were. The packaging of motorcycles in this class has very nice potentials to begin with. As I said in the beginning, the model has made a big step forward for the first time in 14 years. It has become sufficiently competitive.

• Mr. Koyama, do you also feel convinced for setting a record?

Koyama: In each race, riders compete for a fixed number of laps. When the number is 40, the rider who has completed the 40 laps the fastest is the winner. When it is 20, the victory goes to the one finished the 20 in the shortest time. The key is how fast and constantly a rider can run the 20 laps. But it is very difficult to go at a steady rhythm. With the help of various systems including the traction control and power mode, it has become a lot easier to set constant race times. Because riders who can achieve stable race times win, it is a motorcycle to win a race. In the testing at Sugo, we made our last round a 20-lap long run intended for a race final. I achieved constant times without even a 0.1-second-difference. What was more, I had my best lap time for the final lap all of a sudden. Naturally, the tires became burdensome, so I lowered the mode from 1 to 2. And the time reduced in the end. Isn’t it amazing? Moreover, a rider downshifts at quite a speed in a race. To do so, there are many things a rider has to do on his own: shifting down the gear by operating a clutch manually while applying front and rear brakes, and preventing a rear wheel hop by controlling the clutch lever, planning how to recover the grip when the rear tire slips, etc. But this optional quick shifter automatically controls slip once the gear is shifted down without having the rider to think anything special. The rider can simply focus attention on braking. That braking creates great advantages. When comparing a motorcycle with manual clutch operations and one with the quick shifter, braking points are hugely different. The latter can run through overpoweringly. When a rider tries to do the same on a motorcycle with manual clutch operations, the motorcycle sometimes cannot stop. Things like this are very beneficial in actual races.

• For those who enjoy winding roads, too, of course.

Koyama: That is right. Indeed, during a test on this model with and without a winglet, I could tell when it had a winglet at the moment I left the pit lane. After I go out on to a pit lane and turn the pit switch on, the limiter gets activated once 60km/h is reached. At Sugo, the front tire grip felt completely different when I turned the first corner right after leaving the pit lane. It surprised me because I had thought the winglet would start working at a lot higher speed. In reality, I noticed it at the 1st corner, which I normally enter right after accelerating from around 60km/h. Therefore, riders will be able to take advantage of its benefit well even on a winding road.

• Lastly, please give a message to those who are thinking about acquiring this model.