Yuzuru Ishikawa (Honda): The in-line quattro is the best solution for a standard derivative – News


It was really a long time since Honda had seen a motorcycle like it the new CBR1000RR-R Fireblade. A bike with very few compromises, designed practically only to go fast on the track and to return to winning races and (possibly) World Superbike races. In conclusion, a spiritual heir to the RC30, RC45 and RC51 – which was only called VTR / SP by us – even if the designation is a less noble SC 82.

During the test in Qatar we had the opportunity to talk at length with … the parents of the new RR-R. Traditionally, during these tests, one is “assaulted” by the managers of the different areas, very ready to interview the testers who just got off the saddle. This time we attacked the project manager instead, Yuzuru Ishikawa, and the head of engine design, Kensuke Mori, to better understand several of the technical choices that defined the new Honda superbike.

Who I am

A little context. Ishikawa-san has been with Honda since 1993, and alternated between the R&D (the very famous, top secret research and development department, closely linked with the HRC) and the real Honda Motor, first as a specialist in cycling and then, since 2008, as Large Project Leader. Sue, in this capacity, practically all the CBR 1000RR, the 600RR of 2013 and the RC213V-S. But even earlier, in 2002, he did … a little experience, working on the first Honda MotoGP: the five-cylinder RC211V.

Mori-san is younger but he too, in the role of engine driver at R&D, has a past in the sporting if not racing proposals of the Tokyo House. CBR 600 and 1000RR, but also the first NSF250F Moto3.

It is inevitable, given the past of the two, to start talking about their racing bikes, with the inevitable compliments for that masterpiece that was the RC211V.

“It was actually a fabulous bike” Ishikawa replies. “Also because the V5 is a fantastic engine. It is very well balanced, practically does not vibrate, and can reach frightening powers with the same vehicle packaging as a V4. “

One wonders why a road version of that motorcycle never went into production. Many claimed that she was beautiful and ready …

“I cannot confirm this hypothesis, but I can certainly tell you that such a bike was not produced because we could not have achieved the necessary competitiveness in Superbike, given that it would have been penalized a great deal in terms of weight.”

Let’s believe it. But when it comes to the present, how come choosing a four in line instead of a V4? Cost containment?

“Although it’s hard to believe, it wasn’t a question of cost” Mori-San replies. “We had a specific mandate on this bike, and even if it had been more expensive it wouldn’t have been a problem. The answer is much simpler: while we believe that in the case of a prototype, the V4 is the best choice, on a standard super sports car you have to place many components, especially in the exhaust area, and we could not have reached the power levels that we had as goal without irreparably compromising the cycling quotas. “

“In particular, we would have had to open the V a lot to have the space necessary to define sufficiently straight intake ducts, and even arranging the exhaust circuit would have been very complex. Which would have forced us to sacrifice the length of the swingarm, which in turn would have defined a bike too inclined to wheelie. On a prototype, which does not have to comply with the rules of a Euro-5 approved road bike, we have much more freedom and we can make impossible choices for a road. “

“Of course, with a four in-line you get a rather large engine, especially with the 81 bore, which in turn makes it difficult to obtain the lean angles required by such a bike, so even in this case we had to work well on the distribution control, and reposition the starter behind the engine … “

Road against prototype

Since we talked about prototypes, curiosity pushes us to ask because, with the same section, it was decided to define an air intake developed vertically instead of horizontally as on MotoGP.

“It is an example of the different choices we were talking about before” Ishikawa-san replies. “In MotoGP, the V4 allows us, indeed requires us, to turn the air intakes towards the airbox on the sides. On an in-line quattro, the bike would become too wide, so we chose the solution of passing the air through the steering head. “

What about the counter-rotating shaft? What kind of penalties would it bring on a road engine?

“Here also mainly for packaging, because another tree is needed, but also because the counter-rotating tree leads to a whole series of unwanted effects on handling. It is not very in line with our philosophy. And then the wastage of power increases: we absolutely wanted a compact and very powerful engine. ”

What about the rear suspension with the monoshock mounted on the engine instead of the chassis? Why did the sleepers on which the top of the mono was mounted disappear?

“Fastening the upper part of the mono to the frame ensures that all the stresses coming from the rear axle are discharged onto the steering head. A phenomenon that we can avoid using our Unit Pro-Link system, which unfortunately, however, involves an increase in weight which, on such a model, was considered absolutely unacceptable. That’s why the choice to attach it to the engine. “

Curiosity: both Ishikawa-san and Mori-san, just during the trip to Qatar, received a very interesting call. For both of them, a career phase ended on January 31st. Since February 1st, both are in force at the HRC. Mission? Top secret …

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