Cycle News - Archive Issues - 2000's

that has been on the 900 since the beginning, mainly because it provides for better tire selection. The 17 -incher is attached to a 43mm inverted fork, rather than the conventional 45mm unit that was standard on the CBR900. Again there is some weight savings here as the Showa upsidedown unit weighs some 500 grams less than the larger 45mm fork. The new fork also has slightly more compression than the old unit. Other than that, there are no handling quirks with the 929 to indicate that the beefier 45 was still needed. The rear suspension is still a Showa Pro-Link, though the rearwheel travel is up from 125mm to Honda dealers around the world have one man to thank more than any other for the bike that made the greatest difference to their profit and loss accounts over the last eight years. He's 55-year-old Honda R&D engineer and former test rider Tadao Baba. He is the father of the CBR900 and 929, the motorcycle that reinvented the big-bore sportbike category back in 1992. Having persuaded Honda's marketing honchos 10 years ago to jettison the then-widespread fixation on developing bigger, ever more powerful motorcycles that may have been faster but were inevitably also heavier and more cumbersome, and to put him in charge of developing a bike which bucked the industry trend by being smaller but lighter, and so a better all-around performance package, Baba-san has dedicated his professional life to bringing up baby. He's constantly improved the CBR900RR year after year in keeping with his original concept. Inevitably, therefore, he has overall responsibility for the born-again 929. During a break for coffee and another notch in his 40-a-day cigarette consumption chart - "It helps me think about new ideasl" - Baba-san talked about the latest member of the CBR family. Q FirStly, why still only 929cc? Why not a full 1000cc engine like the Rl? Because our n;lain emphasis was to reduce weight, starting Aabove 929cc, because to do so wouJd mean strengthening ity with the engine. Therefore, we chose not to increase capac- the engine construction, and so adding kilos. Of course, we could have made a 1000cc engiDe which was very light (the revised 'OO-model RI, still with carbs, weighs in at a claimed 385 pounds, I I pounds more than its all-new Honda rival), but to do so wouJd risk unreliability, especially as we have added the extra benefit of fuel injection, which does however carry a weight penalty. Given that, together with the RCSl V-twin, this is onda's first-ever fully integrated EFI on a sportbike, whose fuel-injection system have you fitted? Is it a Nippondenso, like other Japanese manufacturers use? Na, it's a Keihin system specially developed for the CBR900RR. It is indeed fully integrated; with 40mm throttle bodies and a single injector per cylinder. This is located on the underside of the intake tract, very close to the butterfly and slanted to point straight at it, to give best mixture control. Also, A since now we have 14 FEBRUARY 16, mOTe over-square engine dimensions of 74 20QO' cue I e n e 135mm. The shock itself is also 360 grams lighter than the one used on the 900 while now featuring a nineposition adjuster vs. the seven-position adjuster on the previous model. . The wheels are bigger at both ends, though they both have less spokes and less weight. The bike will come fitted with Michelins, mounted x 54 mm, compared to 71 x 58 mm on the current model, this allows larger valve sizes for better flow, with a flatter total included valve angle of 25 degrees, against 32 degrees before. This gives a better combustion chamber shape, for improved power. on a 6-inch-wide rear wheel compared to the 5.5-inch wheel on the CBR900. While the changes made to increase the overall power of the C~R929 were readily noticeable at the racetrack - not to mention the crispness of the fuel-injection - it was really the overall weight and size loss package itself. This surely helps the impression of quicker turning, because you feel more close to the mass of the bike, so more part of it for steering and change of direction. happy Q Are youlook as with the CBR's aerodynamic -qualities? It doesn't aerodynamic as the new Rl but does it create a more only lighter better? Q TO swingarm,a did compact engine that is notas well as a protect the riderbuy an optionalthe current for better protection, but allows more forward weight bias This has 3% less drag than CBR900RR, and cusyou consider following Yamaha's lead A tomers can longer tall screen of the triple-stack gearbox design - to shorten the motor? if they wish. We wanted to have a shorter wheelbase for quick hanA dling, plus a long swingarm for improved such an extreme ""'The 43mm upside down forks seem rather small for such suspension conpowerful motorcycle. Is this in order to reduce the trol. But we don't think it's necessary to adopt ~ layout as the Yamaha, because we at Honda already had the best solution - to pivot the swingarm in the rear engine casing. And on this engine, we brought crankshaft and swingarm 20mm closer together, also reducing engine length for better positioning in the frame. We have a 51/49% weight distribution with this new model, with a full fuel load, but without rider, who sits 30mm further forward than before, since we shortened the fuel tank by this amount. So his weight will further load up the front wheel, adding to grip. unsprung weight penalty of using upside down forks? previous models always used conventional suspension of greater diameter. We wanted to reduce Weight irrespective of the type of forks used, so this was the best choice, while retaining good suspension response. With the extra strength of upside down fork construction, deflection is not a problem even with our strong brake performance. a full Q Why didn't Honda usedesign -twin-spar chassis, instead of this semi-pivotless especially after the RCSl the same thickness as the smaller 310mm ones you used before, if weight saving is your objective. Wouldn't it have been better to use the old smaller discs, but with a six-piston caliper from the same supplier, Keihin? replaced the VTRI000's pivotless design with a beam frame in which the swingarm pivots in as well as in the crankcase? Though weight-saving is your main objective, don't you have to add extra material, and so weight, to make the engine stronger at the r~ar to compensate for this? t\ This new frame, which I admit is rather strange-looking, in .t-\.1act is the result of OUf aim to combine side force and twisting rigidity with as little use of castings as possible, since with these it is hard to control the stiffness. But by careful attention to chassis design, and by mounting the engine very strongly in the frame at a total of seven positions, we achieved our desired stiffness, without excessive weight. ,,",It seems from riding the bike as if the weight is much \::XJ.ower than the old one, by the way it changes direction more easily. How much lower is the center of gravity than on the old CBR900? 50rry, but in fact, the cee of gee is 5mm higher than on the existing model! However, this is measuring without fuel, and since the top of the fuel tank is 10mm lower than before, this shows how we have been able to redistribute the fuel load to compact the total mass of rider, fuel and the mechanical bike A vv s A Mention of your choice brakes raises the Q why you would choose toofuse massive 330mmquestion discs of disc diameter counter fade, A withwanted to increasesix-pistonBut intoany case,brakedisc is increased heat capacity. we found that the total weight of a caliper and 310mm We heavier than a 330mm disc with four-piston caliper - so that's why we chose this solution. After inventing a radical 900cc sportbike eight years ago . the form of CBR900, Honda's policy was to constantly refine and update it each year, without major change - until now. Will you follow the same policy of continuous refinement with this new model? As you say, we had foreseen a continual but progressive improvement each year to the CBR900RR specification. But, the introduction of the Rl caused us to consider our best response to this challenge. We decided to bring forward by two years our plans for a projected all-new model, which we planned to launch in 2002. So, this is the 2002-model year Honda CBR929RR, which you can ride two years early. Please thank Yamaha for making this possible! Alan Cathcart A

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