Vol.03 YZ450F

CHALLENGERS OF MONOZUKURI

Story of New Model Development

CHALLENGERS OF
MONOZUKURI

Story of New Model Development

Vol.03 YZ450F

ADVANCE THE DEVELOPMENT USING “FRUSTRATION” AS A DRIVING FORCE

The flagship model of the YZ series YZ450F, which enjoys high popularity in off-road motorcycle racing, has undergone a full model change with dramatic transformation. There were great challenges in its development.

The year 2022 witnessed the joy of numerous victories in off-road motorcycle racing. Among them, winning the 450SX title, the top class of AMA Supercross, attracted tremendous interest. This was the first splendid feat in 13 years since 2009. It was the YZ450F, the flagship model of the YZ series for motocross racing, that led to the victory.
While such a topic was drawing public attention, the YZ450F 2023 model underwent a full model change for the first time in five years. Regarding this latest model, we interviewed the development team members: project leader ISHINO Atsushi; SATOH Katsutoshi, ISHIGAKI Wataru and TAMURA Kouki, who were in charge of testing; vehicle body designer HARUTA Katsuya; engine designer SUZUKI Yuji; and YAMAUCHI Daisuke, who was in charge of electrical components.

EACH MEMBER THINKS AND ACTS ON AN AUTONOMOUS BASIS USING “FRUSTRATION” AS A DRIVING FORCE

The YZ series has distinctive characteristics that have not changed since its birth, which are “powerful, lightweight and compact with easy-to-handle output characteristics and chassis balance.” There has always been a mission to win as well as to be fun. This time it was a full model change of the flagship model that symbolizes the YZ series. But unfortunately, it was a development under the influence of the spread of the COVID-19. You can easily imagine that the development team members must have been under enormous pressure in various situations.
However, contrary to our expectations, the team members gave us a reply as if they had felt little pressure. “Any development project comes with pressure.

We only had to make progress toward our goal,” says Ishino. “We have accumulated experience. We put up flags so that the goal and direction would not waver. We also put importance on autonomy for each member to think and act at his own discretion,” adds Ishino. In other words, he entrusted the members. We can’t help but feel his confidence in them.
However, there was another keyword that became their driving force throughout the development. It was frustration.
“Most of us were involved in the development of the previous model. We had developed it with confidence, but received negative customer feedback, such as ‘too big,’ ‘too heavy,’ ‘difficult to handle,’ or ‘cramped riding position.’ These comments made us frustrated and we wanted to get back at all costs,” says Haruta. The market responded differently from what they had expected. Using this frustration as a driving force, the development team started working on the full model change.

ISHINO Atsushi
YZ Testing Group, Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit

JUST INSTANTANEOUS SPEED DOES NOT WORK. “DURABILITY” IS ALSO REQUIRED FOR A COMMERCIAL RACING MODEL.

Then, the concept of the new YZ450F was set up: “Synchronizing the YZ with Every Rider.” It was a motorcycle that responds to every rider’s needs and also a pursuit of easy handling, which was a big flag put up by Ishino. Components were thoroughly revamped to the point where Ishino can say, “It’s much easier to list unchanged parts than changed ones.” There were also as many things the team struggled with. What particularly stands out in his memory was “balancing weight reduction and durability” and “pursuit of easy handling.”In developing motocross motorcycles, issues of strength and durability always stand in the path of weight reduction. In addition to turning and stopping motions, motocross motorcycles are exposed to violent up-and-down movements such as jumping. Diverse road conditions also put an extra load on motorcycles’ body and engine.

SATOH Katsutoshi
YZ Testing Group, Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit
ISHINO Atsushi
YZ Testing Group, Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit
SATOH Katsutoshi
YZ Testing Group, Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit

“Commercial motorcycles should not break down in a short time causing trouble to the customers. Thus, strength and durability are critically important,” says engine designer Suzuki. Testing engineer Ishigaki also says, “It was difficult to complete this motorcycle as a normal commercial model, because problems with functionality arose even after it received a certain level of positive feedback.”What can be felt from the development team’s comments is that there was no alternative but to repeat the steady effort of designing, test-riding and verifying. Tamura, who was in charge of the motorcycle’s fatigue and strength analysis, recalls his experience saying, “Whether a new motorcycle breaks down or not will come to light after the customer buys it. It takes a long period of time. We repeated tests again and again not to cause trouble to our customers. Because of a newly designed engine, it was a very challenging task.” Every time a problem arose, he reported it with evidence to the designing members, and then repeated tests while considering possible solutions. Each component was newly designed and their goals were set high. Nobody complained in words, but it’s easy to imagine that everything was a challenge to the limit. In fact, it was a repetition of designing, evaluating and breaking. Suzuki says, “I often found broken parts placed on my desk when I returned to the office. Whenever I saw such parts, I thought ‘Uh-oh, it’s over.’”

Each component was newly designed and their goals were set high. Nobody complained in words, but it’s easy to imagine that everything was a challenge to the limit. In fact, it was a repetition of designing, evaluating and breaking. Suzuki says, “I often found broken parts placed on my desk when I returned to the office. Whenever I saw such parts, I thought ‘Uh-oh, it’s over.’”

TAMURA Kouki
YZ Testing Group, Off-road Vehicle Development Division, PF Model Development Section, PF Model Unit

THINK AHEAD AND COLLABORATE CLOSELY. THE TEAM NATURALLY SYNCHRONIZES TOWARD THE GOAL.

It appears that the reason why they were able to overcome such adverse situations was largely due to the fact that the team looked at things in parallel from a higher point of view and found the causes and solutions together to aim at the flag put up by Ishino. Haruta also says, “We did a lot of thinking to protect and evolve the tradition of the YZ series that our predecessors had built up.”
It is also worth noting that the members were engaged in the development with the “make predictions and think ahead” attitude. When communicating with overseas offices, for example, the spread of COVID-19 made it impossible for them to go on a business trip and visit important overseas hubs just like they used to do. “It’s really important to work on-site, assess the severity of ongoing problems and determine the direction of solutions. But as we couldn’t go there, we had difficulties in communication and adjustment. In the case of about a week-long test, we remotely checked the test results and identified the problem in a web meeting at the end of each day.

Then, we proposed a solution by the next morning in local time, taking advantage of the time difference. We repeated this process every day. As we had known the on-site situation to some extent, we were moving things forward by predicting what would be required, thinking ahead and taking action,” says Satoh. It can be easily imagined that what each member should have done synchronized well to arrive at optimal solutions by mutually exchanging thoughts and ideas together with their own experience and knowledge.
Of course, the team had to discuss with other departments in various occasions. In the case of examining the function and performance of cooling and fresh air introduction, after discussing with the creative center over and over again, they were finally able to refine not just the function, but also the exterior.

HARUTA Katsuya
YZ Engineering Group, Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit

PARTS ARE MANUFACTURED IN-HOUSE BY ALL-YAMAHA TECHNOLOGY. SELF-CONFIDENT COMPONENTS THAT THEIR COMPETITORS WOULD BE DEFINITELY JEALOUS OF ARE ALSO PRODUCED.

Their relentless pursuit of weight reduction even extended to a single screw and electric wire, as Yamauchi says, “By adopting a next-generation ECU, we eliminated the relay and tried to reduce the length and weight of electrical components as much as possible, even by one millimeter or by one gram. These efforts finally yielded a world-class result. It was a newly designed clutch 750 grams lighter than before. By integrating the primary gear and the housing into a single unit, they successfully downsized the clutch without sacrificing its strength and also improved the operational feeling.

ISHIGAKI Wataru
YZ Testing Group, Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit
HARUTA Katsuya
YZ Engineering Group,
Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit
ISHIGAKI Wataru
YZ Testing Group, Off-road Vehicle Development Division,
PF Model Development Section, PF Model Unit

According to what we heard, there was no manufacturer in Japan that could produce the clutch complying with the specifications required by the development team, and there were only a few overseas. So they decided to try in-house production of the clutch. Although it was quite a challenge, they eventually succeeded in self-producing the clutch as an All-Yamaha technology with the cooperation of the drivetrain designers and employees of the Hamakita factory. It was a self-confident product that they describe as “our competitors would be definitely jealous of when disassembling the YZ450F.”

YAMAUCHI Daisuke
Project Group,
Electronics System Development Division,
Electronics Technology Section, PF Model Unit
SUZUKI Yuji
YZ-PT Design Group, 2nd PT Design & Development Division,
Powertrain Advanced Planning & Development Section,
Powertrain Unit
YAMAUCHI Daisuke
Project Group, Electronics System Development Division, Electronics Technology Section, PF Model Unit

NOT JUST EASY HANDLING BUT ALSO FAMILIARITY INJECTED. THE COMPLETE MOTORCYCLE ENTIRELY DIFFERENT THAN EVER BEFORE.

In motocross racing, it is important that the motorcycle be easy to handle so that the rider can keep the focus on changing track conditions. To find out how the rider feels about the motorcycle even if there is no problem with the analysis, and also to prevent sudden unintended acceleration when opening the throttle of this high-power motorcycle, the development members carried out tests over and over again. Furthermore, in order that the rider can easily fine-tune the engine characteristics with the special app Power Tuner, they have developed an easy tuning program, with which the rider can easily adjust the engine mapping from a smooth mapping to an aggressive mapping in a one-dimensional manner.

SUZUKI Yuji
YZ-PT Design Group, 2nd PT Design & Development Division, Powertrain Advanced Planning & Development Section, Powertrain Unit

Not just the engine, but they also invested a substantial effort in the YZ’s symbolic aluminum bilateral beam frame. As they had received negative customer feedback about the previous model’s “stiff steering”, more than ten aluminum parts were fully refurbished. A number of changes were made to the frame; the main pipe was lowered by 15 mm to change the twisting position and the internal ribs and the engine suspension plate were newly designed. However, just the 15-mm reduction threw the vehicle body off balance during the development, making the motorcycle more sensitive to external disturbances in weight reduction. Furthermore, in order to achieve their goal, they also improved the vehicle body itself through trial and error, such as downsizing the air box. Although the team members enhanced step by step the operability including turning performance under such circumstances, everyone says that it was very difficult to find a middle ground for compromise.
“Motocross motorcycles are used in a wide variety of road conditions and environments. We had our test riders ride prototypes in various locations to gather their opinions. After their test-rides, we made changes to the frame such as drilling holes and shaving off the frame by a few tenths of a millimeter based on CT scan images. After all, there was no alternative but to test-ride and repeat modification,” says Satoh. This repetitive process of test-ride and adjustment by test riders and engineers results in higher sensory evaluation and easy operability, and eventually leads to excellent steering performance unique to Yamaha motorcycles. It’s not too much to say that the holes on the inward side of the frame for rigidity balance are the clearest proof of the team members’ struggle in their relentless pursuit.
Regarding the new YZ450F, which has been refined and completed as mentioned above, the development team says, “It’s an evolution that is completely different from what we have seen before.” They adopted mechanisms that create a sense of affinity with the motorcycle and enhance the user’s enjoyment, which are the tool-free adjustable front suspension, wide-range settings with the advanced special app Power Tuner as well as easy handling of the motorcycle itself.
What kind of evaluation did this motorcycle receive? In the US, where motocross motorcycles are extremely popular, Shootout and Press Test are held annually where new models are gathered together from all over the world so that top riders and media professionals thoroughly examine them. It is known that receiving the same positive feedback from the evaluators is quite difficult because these various riders generally give a variety of different remarks.
However, the YZ450F earned a lot of positive comments such as “compact,” “lightweight” and smooth” as the development team had expected. “Without leading the evaluators to give us positive feedback, we obtained consistent good evaluations,” says Ishino. It was a moment when the hard work of the development team members as well as many other colleagues and divisions involved were finally rewarded.
The evaluation results traveled around the world and orders for the YZ450F flooded in, quickly reaching the upper limit of the production plan. The 2023 race season will come into full swing soon. Let’s have great expectations for the success of the new motocross motorcycle that will lead the next generation.