by Ken Hutchinson

CBR600RR First Ride

If one bike has dominated the supersport class over the past two decades it is the Honda CBR600. From the venerable Hurricane that swept the new AMA 600 Supersport series in 1987 to the F4i that Fabien Foret rode to the 2002 World Supersport Championship, the CBR engineers have managed to concoct the ideal mixture of streetbike versatility and race track performance for 15 years.

But the 600cc sportbike class is not what it once was. Formerly an entry-level market, the middleweights currently deliver a Roy Jones Jr.-like performance punch through their 15,000 rpm redline. As such, the new CBR600RR is the first Honda sportbike to be developed as a race machine first, then getting the requisite street capabilities put in later. We are looking at a new dawn in the evolution of the middleweight class.

When Honda unleashed the ground-breaking CBR900RR it took the liter-bike class to new levels of performance and handling, and inspired speculation that a middleweight version would soon follow. A decade later the folks at Honda have finally had enough of our whining. Cinch up your chin-strap and tighten up the boot-buckles boys and girls because the double-R version of the CBR600 has arrived, bringing a potent new challenger for middleweight supremacy.

The CBR’s press introduction took place at Las Vegas Motor Speedway, home of three-time world champ Freddie Spencer’s Performance Riding School. Freddie and his instructors Nick Ienatsch and Jeff Haney were part of the support team on hand and were available throughout the day to offer insight on navigating the shortened 1.1-mile infield road course of LVMS. Both Honda and Dunlop had a great support staff on hand to ensure the bikes were properly set up for each individual rider.

2003 Honda CBR600 Review 

Walking up to the bike for the first time might cause a person to entertain the thought that this is in fact a street-going version of Valentino Rossi’s RC211V MotoGP monster. That’s just what Honda was aiming for. The distinct RC styling is not lost on the striking appearance of the CBR600RR. From the aggressive aerodynamic bodywork and single under-seat exhaust on up to the black aluminum frame and massive GP-inspired braced swingarm, it’s obvious this is intended to be a hardcore carving weapon.

The CBR’s R&D department, headed by Large Project Leader, Hiroyuki Ito and Chief Engineer, Hideo Koide really did their homework. By utilizing the lessons learned during the development of the RC211V they were able to implement similar technological innovations on the 2003 Honda CBR600RR. The Unit Pro-Link rear suspension and revised fuel cell location were two key components to reaching their goal of concentrating the component masses and rider at the center of the motorcycle. The lighter, more compact engine and revised rider position complete the package that is being touted by Honda as the most advanced production motorcycle it has ever produced. After thrashing the RR all day around LVMS, it’s hard to argue against that point.

The new RR is extremely smooth and well-balanced, everything felt right from my first lap to the last. This is one of the most rider-friendly bikes I have ever sampled, continuing a long-standing Honda tradition. I spent the first two hours searching for something that didn’t work for me, and about the only thing I could come up with was that I really wanted to ride the yellow bike, not the black one I was assigned. My notepad was filling with praises as the laps piled up. The cornering confidence that this machine offers is sure to make it a contender for top honors at both the track and the canyon, although only the most talented riders will be able to tap its ultimate potential.

Once in the thin saddle I found a much more comfortable bike than expected. Although it’s small in stature and has fairly low bars, it’s not quite the torture rack as other sportbikes on the market. Ergonomics are similar to the F4i, with the key difference being that the rider is now 70mm closer to the front wheel than F4 pilots. The peg-to-bar distance should be able to keep riders of all shapes and sizes comfortable enough to survive a long day riding, with the exception perhaps for those of you well above six-foot. The clip-ons aren’t too low, and my legs weren’t cramped despite the high-mount pegs. Even after 100 miles of track time, I didn’t want to get off this nimble little rocket.

It didn’t take much time on the track for me to realize why Honda’s ‘Mass Centralization’ design philosophy is worth all the effort. By keeping the weight centralized around its roll axis, rider input is met with less resistance allowing for smoother and quicker side-to-side transitions.

The F4i has a 0.2-inch shorter wheelbase and is three pounds lighter than the RR, all of which says the old bike should steer quicker. But Honda’s mass centralization philosophy has endowed the RR with much greater nimbleness despite nearly identical steering geometry. Back to back testing of the F4i to the RR showed increased turn-in response, easier side-to-side transitions, and a more precise attack on a chosen line.

The Unit Pro-Link system, borrowed from Dr. Rossi’s rocket RC211V, is cited as a major reason the GP bike was so successful in the MotoGP series. Rather than the upper shock mount connecting to the bike’s frame, the Unit Pro-Link contains the rear shock within the swingarm itself. The linkage bolts up to the bottom of the shock with a series of linkage that ultimately attaches to the bottom of the frame. This system helps isolate the chassis and rider from potentially upsetting rear wheel input under acceleration.

One of my first and most important moments of clarity regarding the UPL came at the exit of the last of the track’s three left-hand corners. Granted, I’m no Rossi, but I could regularly break the standard equipment Dunlop 208 rear tire loose on the exit while trying to keep my speed up heading towards the entrance of the last corner. The track’s final turn is a double-apex 180-degree sweeper leading to the short front straight. At first I was duped into believing my keen riding skills were responsible for keeping the back end under control, but upon further review the new Unit Pro-Link rear suspension likely had more to do with it.

In practice, the UPL transmits feedback from the rear wheel in such a way that it provides an incredibly smooth riding experience. Describing exactly how the system works and why is beyond my burgeoning journalistic skills. Just know that it is very smooth and reduces the chance of getting spit off when the rear tire regains traction under acceleration. And as far as I can tell it also smooths out road imperfections better than the street-biased F4i. Granted, the surface at LVMS is smoother than virtually any public road in America with the exception of the track’s second left-hand turn which had a big imperfection right in the middle of it, so it is difficult to proclaim the suspension as ground-breaking before logging some time on real-world surfaces.

Still, the Unit Pro-Link set-up handled that particular pavement wart better than conventional suspension of the F4i I tested during the intro. Riding the two bikes back to back revealed that the CBR600RR’s suspension did a much better job of soaking up the bumps. Although I have not spent much time aboard the F4 during the last couple years, the 2003 model F4i did not offer the precise handling of the RR when propelled through the twisty circuit. Instead it felt ungainly in comparison to the more focused and agile RR.

The innovative Unit Pro-Link suspension of the CBR600RR on the other hand works in harmony with the 45mm conventional Showa cartridge fork. Since the new Kawasaki ZX-6R is the first 600 to come equipped with racier inverted fork, I asked suspension and handling engineer Shin Watanabe whether the days of conventional forks were numbered. He insisted that for this size of bike, the fully adjustable conventional fork offers the best possible combination of low weight and high performance.

All of these suspension components are attached to an all-new frame that has been fine-tuned for the track right out of the box. Similar to the concept behind Yamaha’s Controlled-Filled Casting system, Honda’s Hollow Fine Die Cast (HFDC) technique produces lighter, stronger chassis parts because of the vast reduction of the number of air pockets that naturally find their way into traditional die-cast components. Honda says the frame’s wall thickness can be as thin as just 2.5mm where maximum strength is not needed. The new steering head has slightly reduced torsional rigidity at its center while it is stiffer in the area surrounding the steering head. Honda says this allows the wheels to track smoother over bumps while the bike is leaned over.

That matte-black aluminum frame cradles the compact and powerful inline-four-cylinder engine that emits a menacing growl as its 15,000 rpm redline nears. Honda’s goal was to create the most powerful and compact motor in the class with a stratospheric redline. They reached these goals by stacking the mainshaft above the crankshaft’s centerline, and then relocating the countershaft closer to the crankshaft. This triangulated profile allows the engine to be 30mm shorter. This allowed the swingarm pivot point to be moved closer to the crankshaft and although the installation of its 573mm swingarm is 43mm longer than the F4i, it still retains a short 54.7-inch wheelbase. Moving the engine closer to the front wheel facilitated the need to redirect the exhaust port angle an additional 30 degrees downward which made room for the header design. The headers curve tightly along and beneath the engine before exiting out the single “center-up” exhaust.

Combined, these efforts to move the weight bias forward offers a more progressive action for the rear suspension and the potential for greater corner speed with improved front-end traction. The swingarm design is the key to the mass centralization goal applied to the CBR600RR. The press-forged right side has a decidedly GP-inspired appearance while the extruded box-section left side offers a more traditional looking braced design reminiscent of the 900/954RR. Those two pieces are welded to a cast crossmember which serves as the pivot point and mount for the rear shock rather than the traditional boss mount at the rear of the frame.

By relocating the top shock mounting point and moving the motor forward, it gave the design team the space necessary for the new fuel cell. Just as on the RC211V, fuel is stored directly over the engine with 2/3 of the storage capacity located below the frame spars, contributing to the centralized mass design ethos of the CBR. Beneath the plastic cover that resembles a traditional fuel tank is the 15-liter airbox and room for 4.8 gallons of gas. Keeping the fuel in this lower location means the bike’s dynamic handling is not adversely affected by fuel loads. For what it’s worth, I never noticed the CBR reacting any different in the handling department following the fuel stops made during our day thrashing this screamer.

Go-juice is supplied to the engine by a Dual Stage Fuel Injection System (DSFI) which employs not one, but two injectors per cylinder. This system was originally utilized in Formula 1 cars before making its way to the MotoGP bike and on to the 600RR. Four 40mm Denso throttle bodies take care of business when the engine is turning below 5500 rpm. Beyond that limit, a quintet of injectors located inches above the velocity stacks within the airbox make their contribution under the careful management of a 32-bit ECU.

The system helps the CBR to make very linear power. Acceleration increases seamlessly as the second injectors kick in and provide the fuel necessary to accelerate up to redline. The F4i made a rider wait for its punch to finally arrive in its upper midrange, but the RR’s power is always available. There is no huge “hit” of power, it just continues to pull and pull until you hit the rev limiter, making for a rider-friendly powerband with no shortage of thrust.

Once the bike was rolling, all I had to do was keep pulling gears in the slick tranny before the next corner arrived. Fortunately, the brakes have been upgraded on the RR, with front rotor sizes increasing from 298mm on the F4i to 310mm for a greater swept volume. The four-piston calipers provided great power and never gave a hint of fade despite the constant abuse.

Keeping track of rpm and speed is just as effortless as riding the bike. A new easy to read instrument gauge cluster consists of an analog tach positioned between a digital speedometer on the right and temperature, clock and fuel gauge displays to the left. A shift indicator light is also standard equipment. Thin gauges, LED tail light and all-new Line-Beam headlights are just more of the weight-conscious components that represent the constant improvements made by the CBR engineers.

After five hours of riding and more than 100 miles of track time, I was mentally spent heading into the final session. By then we had a scrubbed-in set of GP-compound 208s egging me on for more track abuse. I could not resist the chance to spend another 20 minutes with this fine machine so I suited up and made my way out of the garage and back onto the speedway.

The sun was setting in the distance which caused quite a glare through half of the nine corners. I was quite happy that a representative from Shoei was there to provide their new Z Two and tinted shields for those who cared to sample their latest lids. As I was doing my best to tax the GP-compound tires and the razor sharp handling of the CBR600RR it was starting to get difficult to avoid being distracted by the Thunderbird air demonstration team that were doing their aerial maneuvers in F-16s overhead.

That and the NASCAR stock cars that had commandeered the banked portion of the speedway provided a surreal backdrop as I put the RR through one last session. With grippy rubber and greater familiarity of the infield course, the new CBR proved it could easily be one of the best middleweight sportbikes to ever hit the market. This highly-developed machine should give the other 600s a serious run for their money both on the track and the showroom in 2003.

With such intense competition this year, it would be impossible to suggest a winner without putting the new middleweights up against each other in a back-to-back comparison. For the time being, you will have to be content knowing that the CBR600RR is a stunning new sportbike that I can’t wait to ride again. The Honda CBR600RR should give the other 600s a serious run for their money when it hits the showrooms next month.