"The CBR must be a more versatile motorcycle that still has top performance, but is easier for the average person to ride on the street," remarked Tadao Baba, the now-famous project leader for Honda's open-class CBR-RR series since its inception back in 1993. "We feel the [Guess which brand he mentioned? --Ed.] is more of a racetrack-only, experts-only machine."
Since taking the world by storm with the original 1993 CBR900RR, Honda has watched the open-class sportbike landscape change drastically in the last four years. Power outputs have jumped dramatically, with chassis and suspension performance rising at a similar pace. Today's big-bore sportbikes are faster and more nimble--in both track and street environments--than ever before.
Despite all this excitement about horsepower and speed, Honda has always prided itself on the versatility of its sportbikes. By versatile, we're talking about user-friendliness; the ability of a motorcycle to accommodate riders of varying degrees of skill. Hondas have always had the reputation of highly polished packages that reflect countless hours of R&D.
The debut of the Yamaha YZF-R1 in 1998, however, forced Baba and Honda to ratchet up their development program and introduce the 929 two years earlier than planned, in 2000. And now, with Suzuki's GSX-R1000 having turned the sportbike world on its ear in 2001, along with a redesigned R1 (see AT's First Ride, page 54) making its appearance this year, it's pretty obvious that subtle refinements and new paint weren't going to cut it for 2002. So the big CBR receives a slew of substantial upgrades, the most obvious of which is an increase in displacement from 929 to 954cc. User-friendly or not, Honda is looking to back up its new "Performance First" sales slogan. It seems the open-class performance wars are getting just as hot as the 600cc category.
LOSE WEIGHT/GAIN POWER NOW,ASK ME HOW!
Rather than take the prohibitively expensive route of designing and producing an all-new engine in their quest for more power (and performance), Baba and the Honda engineers took the usual path of trimming weight while squeezing some more ponies from the same basic engine. The problem is that the 929RR was already pretty lean (it was the lightest of our BOTY open-class contestants), with an engine design that reflected that same philosophy (not a whole lot of room to increase displacement).
This meant that the engine gets its displacement increase strictly through a 1mm larger bore. And even that was a push; there is now only 1.5mm between each aluminum composite cylinder sleeve. Compression ratio was raised a smidge from 11.3:1 to 11.5:1 via new piston assemblies that, despite being larger, are six percent lighter. The pistons are starting to resemble Formula One pieces, with almost no skirt to speak of; the wristpins are now essentially the same size as 600F4i units. Cam timing duration was increased three degrees for both intake and exhaust, with a corresponding three degrees more overlap for better breathing at high rpm. Single exhaust valve springs replace the previous dual units for a total of 2.5 ounces less unsprung valve train weight.
Fuel injection throttle bodies are now 42mm (up from 40mm), with new injectors featuring 12 laser-drilled jet holes (from the previous four) for finer fuel atomization; the second-generation PGM-FI's ECU is also much more powerful and quicker-computing. Airbox capacity is the same, but now breathes through inlets that snake over the frame rails resembling ram-air ducts, but aren't; there are no intakes on the front fairing.With such a lean design, weight pared off the motor is now measured in grams. The new starter motor using "neodium" magnets is much smaller, and is 400 grams lighter (nearly a pound, for you non-metric heads). Computer-aided design helped shave off over 160 grams from the crankshaft and engine cases. The muffler is now completely constructed out of titanium (except for the outer covers), shedding another 440 grams. In sum, the new engine assembly weighs two pounds less than last year.
The CBR's chassis also underwent extensive changes, aimed at weight reduction and/or improving overall rigidity. Modifications to the steering head casting thickness and the D-shaped lower frame brace increase torsional rigidity 8.6 percent (while actually decreasing lateral rigidity 3.6 percent--more on that later), with tapered roller bearings now used in the steering head. Lighter, redesigned rear castings utilize repositioned rear subframe mounts, which, combined with the reshaped fuel tank (10mm shorter and flatter), help slim the 954's profile between the rider's knees.
The swingarm is all-new, utilizing technology gleaned from HRC's racebikes. Instead of the previous unit's extruded aluminum beams welded to a large pivot casting, the majority of the new swingarm uses large, stamped aluminum sheet box-sections that are welded together with a smaller pivot casting. Although physically larger than the previous swingarm, the new component scales in 340 grams lighter. The rear shock spring is 250 grams lighter (thinner wire, same spring rate), while the shock itself sports a more linear damping rate for better high-speed bump absorption. |
