Motorcycles Technology

CBR600RR Engineers Talk


The CBR600RR has risen again under the concepts of “Specs to win a race”and “Stress-free total control”.
“You can forget the notion of the inline 4-cyilnder engine. Go over engine types starting from a single-cylinder to find out what suits this model the best.”That was what young engineers were told by Large Project Leader (LPL)Ishikawa at the start of the development.
With Mr. Koyama, the Series champion of the 2019 All Japan Road RaceChampionship ST600 as a test rider, the development was kicked-off, believe it or not, for the race model first before the mass production model.
I had a long interview with the development team members to understand what their aspirations were for creating this model.


Tomoyoshi Koyama (Professional rider)

Winner of the GP125cc class of the All Japan Road Race Championship in 2000. 
Participated in all the 125cc-class races of the FIM Grand Prix World Championship from 2005 to 2010.
Competed in the Moto2 in 2011 and 2012 and the Asia Road Racing Championship from 2013 to 2017.
Raced on the CBR600RR in the All Japan Road Race ST600 Championship from 2018, scoring a Series Champion in 2019.
Served as a development rider for the CBR600RR.


Yuzuru Ishikawa (Large Project Leader)

Started his carrier at Honda in 1993. Designed frames for models including the CBR1100XX, RC211V, CBR1000RR series, RC213V-S, etc.
Large Project Leader for the CBR1000RR/600RR series, CB125/150/250/300R and CBR1000RR-R.
Owner of a 2012 CBR1000RR and CB150R.

1.Aiming for specs to win a race

-Please tell me how the development started.


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.


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.


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.


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.


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).


Daisuke Doyama (Large Project Sub-Leader)

Started working for Honda in 2007. Responsible for fuel research for models such as the VT1300CX, CB1100, CBR1000RR, CBR600RR and RC213V-S.
Wore two hats for the CBR600RR development as an Assistant LPL and fuel system researcher.


Keita Shigematsu (Engine Research)

Joined Honda in 2004. Belonged to the research team of inline 4-cylinder engine for super sportbikes.
Involved in mainly large-sized models such as the CBR1000RR, CBR600RR, CBR250RR and CB1100 after taking part in the development of the 2005 CBR600RR.
Developed race engines for the Moto2, the Super sports World Championship, and the ST600 class of the All Japan Road Race Championship.

2. Engine infused with 14 years of aspirations

-What sort of development did the engine team do?


First of all, Mr. Ishikawa told us to write off all the engine types once and think of an engine out of the box, because he wanted to beef up the racing potential of a motorcycle in the stock condition to be sure to win a race.
I was surprised to hear that, but we anyway reset ourselves and did a zero-based review on each style of V, L, parallel, single-cylinder, and so on to see how we could increase the RPM and horsepower output.
In the end, we chose a style similar to the current inline 4-cylinder engine type.
Here we realized again that after all this style could output the highest horsepower.
From that point, for what kind of technologies to apply to achieve high revolutions and high output, we didn’t stay idle doing nothing, but we were hoarding technologies below the surface for “someday”. This was even though for some time during the period, the 600 was not in the lineup for commercially available motorcycles.
Those technologies included cam dimensions, pistons, and throttle bodies to be more specific.
I myself poured into this engine technologies I had accumulated for about 14 years.


In the aspect of races, we discussed with Mr. Koyama to get some insights on essentials and put them into shape.
On the other hand, it was not that we just sat around doing nothing, but we had been doing different research behind the scenes.
So, everyone had many different aspirations. And this time, these aspirations were united with great timing.


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. 


Throttle body diameter was enlarged from
φ40mm to 44mm to ensure intake air volume for higher engine revolutions.


Besides, non-linear machining technology was used to process the throat of the inlet port with an axis tilted relative to the valve center axis.
Connection of walls became smooth to improve intake efficiency.

-Will development become difficult if you start off with a race machine?


Once an ideal torque curve has been established in mass production development, race machine development is easier because its peak will be raised from that basis.
Whereas, after a winning peak performance is obtained on a race machine, getting a torque curve also usable for mass production vehicles requires delicate development for which simulation will not suffice.
We repeated multiple trials and errors like, shifting ignition timing or cam dimension by 1 or 2 degrees, changing air funnel length by 1 or 2 millimeters, etc., to settle on the current specifications at last.
We had many test values stocked up for 14 years.
So, it was nice that we had a rough idea how far we could go. We were able to accomplish the development in the limited time frame because the technologies accumulated for a long time had finally borne fruit.


Listening to you, I am impressed to learn that this engine is infused with everyone’s aspirations. 
Compared to the race machine I currently use, this engine revolves very well at the higher rpm.
Moreover, the feel at the time the throttle began to open was very mild.
The electronic control systems were also surprisingly very helpful.
I thought I was in control of the throttle with my own operations, but in reality, the test motorcycle with the electronic control systems was very easy to ride and fast.
Doing testing on the race track of Sports land Sugo, not only was I astonished by the engine speed on a quick ride, but what was the most stunning was that I could keep going at the speed of 0.5 or 0.6 seconds short of the record I had marked on a race machine at the Sugo track.
As I am not supposed to roll over during a test, I run at the limit where I do not risk that. 
Yet, this motorcycle ran in a stable manner at a speed almost as fast as my race machine record which I dared taking risk. It was eye-opening.   
The Sugo race track becomes flat after the 10% upslope following the final corner exit.
On this motorcycle, I felt only a split second of lift there. 
This means the motorcycle is powerful.


Cam profile was meticulously tuned based on the 14 years of accumulated technologies.


Inlet valve closing was delayed by 5° while exhaust valve opening was hastened by 5°.


-Please tell us details of the technological progress. 


Although the basic engine layout stays almost the same from the previous model, the new model incorporates technologies, such as material change, advanced in the course of development of other models in the past 14 years.
In addition, the cylinder head is designed anew to improve the area around the ports carefully for higher air intake efficiency.


Ms. Shiozaki adopted high strength material to the valve spring for achieving higher rpm without altering this package.
Furthermore, the cam shaft and crank shaft are made of high strength material that resists the revolutions to go as high as 16,500rpm for racing.
Naturally, all this is for making the machine to output higher power to win a race. If it is broken, all would be lost.
This engine was used in a variety of races such as the Moto2(from 2010 to 2018), the Super sport World Championship and the ST600 class of the All Japan Road Race Championship.
All the technologies fed back from these actual race tracks are put in this engine.  
The best part of development, I think, is to verify a hypothesis.
For this particular development, I have especially a strong attachment to the engine cylinder head.
As engine rpm becomes higher and higher, troubles like a cracked combustion chamber occur.
Application of higher rpm was in such a domain that we formed a hypothesis that the cylinder head should be cooled down by water to prevent trouble from happening.
However, the layout did not allow expansion of the water jacket.
As a solution, Ms. Shiozaki came up with a design using a long reach plug to increase the water jacket capacity successfully.
Cooling an engine properly with water is an ordinary process, but it is difficult to do it in the limited area inside the cylinder head.
Layout change to use a long reach plug that is longer by as little as 7 millimeters boosted the water jacket volume and solved the thermal issue drastically.
I reaffirmed the importance of cooling. And it was wonderful to share among three of us in the engine development team that we had had a correct hypothesis.


Water jacket to the cylinder block. Improvement of its cooling performance made the higher revolutions possible.


Owing to the adoption of long reach plugs, the water jacket can be assembled to the location closer to the combustion chamber where the cylinder head can be effectively cooled.


Eiko Shiozaki (Engine Design)

Developed multi-cylinder engines as an engine designer, mainly inline 4-cylinder engines including the CBR1100 XX.
Joined again the CBR600RR project for the first time in 14 years as a project leader this time, after recent involvement in the CRF1000L and GL1800 developments.

-Is it common to use a long reach plug?


I see many cases these days.


More and more models carry the part in recent years.
A cylinder head distorted by the heat from high revolutions deteriorates engine’s sealability for times of engine disassembly for, for example, gasket replacement.
Such an engine eventually exerts significantly less horsepower after a long time, so I wanted to do something about it.


Even though called a long plug, it is longer only by 7mm or so.
For keeping maintainability of the plug on the engine mounted on the vehicle, we checked compatibility with tools and assembly/disassembly movement paths.
Like this, we made ingenious efforts in areas out of sight.
As a result of the improved cooling performance, I believe the engine has fulfilled the required specs.

-Is it true that you did a zero-base review on engine types?


LPL Ishikawa gave us the instruction at the earlier stage of the development in a nonspecific manner by saying, “Could you think about it?”
Mr. Ishikawa is an LPL who often takes such an approach. (laughs)
It was to remove constraints once and study which engine would give the highest horsepower.
Of course, we really considered all the types.


That was Mr. Ishikawa’s instruction, but I am sure he likes the inline-4 engine the best.
Whichever type Shigematsu had selected, in the end he would have said that we would achieve the horsepower with an inline-4.
Though Mr. Ishikawa told us to start all over from the single-cylinder engine, the single-cylinder was not an option for me.
If the twin-cylinder had proven the best, we would have investigated once more what would make it so to devise a way to reflect the outcome to the inline 4-cylinder engine. 


-So, the inline-4 is the best. Why is that?


Because it is only the inline 4 that embodies the “600 spirit” handed down to the senior designers.
It gives an extremely smooth revolution feel during a ride which can be savored only on the inline-4.
Although the V4 cylinder engine produces a V4-specific pleasant feel, such a revolution feel is only made real by the inline 4-cylinder engine.
I assume everyone has watched the video uploaded to the CBR600RR product website. The sound on the straight track right after the motorcycle has climbed up the 10% upslope of Sugo race track can probably be emitted only by the CBR600RR.

-Do you feel the same, Mr. Shigematsu?


Yes, I like the inline-4 the best. Maybe because I have spent 90% of my carrier at Honda on the inline-4, whereas only 10% is on the dual-cylinder engine. (laughs)
We have considered different types of engines but decided on the inline-4 at the end.
I have been working on the CBR600RR with Mr. Doyama since I joined Honda.
Certainly, when asked about the 600, I would say, I prefer this bore stroke of 67.0×42.5mm.


Takayoshi Kitano (Engine Research)

Joined Honda in 2016. Involved in research on engines such as the CB1000R, CBR650R and CBR1000RR-R.
Engaged in the inline 4-cylinder engine since the start of his Honda career. 
Became a PL for the first time for the CBR600RR. The youngest member on the team at the age of 23.

-What area did you take on in this development?


I took care of die parts development. What I struggled with the most among them was the valve spring.
As the engine revolutions became higher and more power was produced, higher load was naturally applied to the valve system, damaging the inner spring at first.
Adoption of the high strength material made it possible to establish the specifications for achieving both the targeted output and durability.
I am really happy to see the mass production happen.

- LPL, what was your intention to ask for the zero-base review in the first place?


The development of the CBR600RR has been resumed after a long interval even though its research was ongoing behind the scenes. 
Thus, instead of taking off based on the existing conditions, we needed to go through the process to understand well how the current technologies would work on the dual-cylinder engine, 3-cylinder, etc., before consequently choosing the inline 4-cylinder.
Otherwise, we might fret about not going for the dual-cylinder or 3-cylinder engine.
This is absolutely not good. I thought we should prepare ourselves to decide on the engine that we would work on.
I wanted to organize all this.


Thanks to Mr. Ishikawa for leading us to such a review in the beginning, we could develop this engine with unwavering integrity throughout. 


Knowing that the inline 4-cylinder engine would be selected in the end, the team confirmed all the engine types to accomplish the specifications to win a race.
It was an episode that illustrated serious passion toward the CBR600RR.


The valve spring damaged by higher revolutions has become tolerant to them after new material was applied.

3.Designing a frame to win a race

-What about the frame team?


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.


Kuniaki Wakamatsu (Frame Design)

Entered Honda in 1997. Designed parts around wheels including brake suspension systems for the CR series.
Took on the frame design for race machines (the RC211V and the RC212V) from 2002 to 2009. His best memory was Nicky Hayden’s MotoGP victory in 2006.
Involved in the RC213V-S and CBR1000RR-R after being transferred back to mass production development.

-While looking at the race trends…


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.


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.


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?


Shogo Nishiyama (Steering Stability Research)

Employed since 2006 and assigned to the frame manufacturing department of the Kumamoto Factory. Hoped for undertaking CBU function testing taking advantage of his racing experience and transferred to the current CBU research department after spending some time in the certification testing department and product engineering department.
As for his racing career until 2015, competed in the Kyushu Championship in addition to one-off basis participation in the All Japan Road Race Championship and the Asian Road Race Championship.
Raced in the Suzuka 8 Hours in 2012 and 2015.


During the study of the frame dimension, we tested at Sugo the design with a wheelbase different from before.
In the beginning the times were not good.
Mr. Doyama and I agreed on trying a couple more patterns before giving up.
When there was one more pattern left to check and we were to quit if we didn’t get a good result, we tested a more rigid design in the area around the rear axle.
Suddenly the time sharply dropped, which encouraged us to continue a bit more.
We tried 2 to 3 more levels afterwards.
Then, times improved step by step, and we finally obtained the result that looked alright.
We succeeded in the design around the end piece of the swing arm, which can be applied both to a race machine and a mass production model. 
I am glad that this design contributes to handling nimbleness of a mass production motorcycle and to a better rear tire grip feel of a race machine.

-So the design was discovered.


Right. When we tested in a little bit lower speed range, we thought this would be enough.
But thanks to Mr. Koyama, the design has become perfect after testing at a race speed.


Swing arm longer by 3mm than before. And design to increase rigidity around the end piece crucial for time improvement. (Image at the bottom)
Small difference in machining such as chamfer width of the spot face, in addition to the more rigid collar in the center, made times improve.

4.600cc, the best package to savor the joy of maneuvering

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


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?


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.


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?


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.


Sho Koyano (Dynamic Force Research)

Hired in 2011. Took part in development of the CBR150R, CB125/150/250/300R, etc. The CBR600RR is his first large model.
Owns a 2009 CBR600RR.

-The new feature is a winglet.


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.


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.


The team tuned profile, installation location, angle, etc., by the millimeter in the wind tunnel lab and during running tests.


The model is designed with stepped protrusions below the front cowl whose profile and location were fastidiously deliberated by the millimeter. As a result, air coming from the front is separated and kept from flowing inside the cowl, contributing to reduced air resistance.


Concavity on the upper surface of the fuel tank shelter lets riders lower their head by 10 mm.


The screen is stood to completely protect the rider in a “heads down” riding posture.

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

-Is it the control system that prompts maneuverability?


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.


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.


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


Honda successfully incorporated its latest electronic devices used to the 213V-S to this new model at a low cost, through efforts such as carrying over existing devices like an ECU. It is certainly a good buy.

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


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.”


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. 


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.


Hiroyuki Akiyoshi (Control Systems Development)

Joined Honda in 2013. Participated in development of mainly larger models such as the CBR1000RR SP2, CBR1000RR, CRF1100L.
Also, involved in development of the CBR1000RR race kit model and race motorcycles for the Suzuka 8 Hours.
Plans to purchase a new CBR600RR to eliminate the cry-wolf reputation.

-Impressive control systems.


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.


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.


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.


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.


-What was your impression on riding the model, Mr. Nishiyama?


As originally I participated in races on the CBR600RR, I took on the task of steering stability confirmation.
During my career, this was my first time to carry out such delicate tuning of the winglet in this development.
Just 1mm of difference in height of the protruding area of the winglet called the wing end plate made handling change.
Besides the winglet, there were such tuning points here and there such as a hidden area inside the cowl.
It was incredible to see the scales of changes caused by minute tweaks.
The ease of ride is the fruit of such fine tuning.
Riders will probably be surprised once on the model.


In the course of the development, the design team and research team went through various interactions to discuss in a meeting after each test.
There were many unbelievable stories. 
It was like: “do you do that?”; “how many millimeters?”; “1mm, really?”, until the very end.
Looking back now, these trivial details were crucial.
But back then, we were running out of time to release drawings.
Those who ride and test are the only ones to take such a fastidious approach to find out small details.
As a designer, I was only half convinced. (laughs)
But I conducted this development with an ambition of having their fastidiousness pay off.

-How about you, Mr. Doyama. What did you think about the riding feel?


We had to create a mass production model whose target riders were ranging from regular users including novices with a license recently acquired to those like Mr. Koyama at the pinnacle of racing.
We built it while encountering difficulties like the 1mm story mentioned earlier and the scary incident during the traction control check, then took it to the race track for Mr. Koyama to set a record.
It was an extremely challenging development.
This motorcycle is truly easy to ride, easy to turn, exhilarating to ride and yet fast.
It has all the appeals a motorcycle can offer.


-Is it the winglet which facilitates a corner turn?


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.


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?


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.


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.


I would like many people, novices and old pros, to ride this motorcycle.
You can experience of the joy of maneuvering at any event.
Not only showing fun of sportbikes, but the CBR600RR will be your future long-time partner. Please try experiencing it.