Powersports / Motorcycles / Sport / CBR600RR / Development
The 2007 Honda CBR600RR: A New Dimension--Literally Speaking--in 600cc Sportbike Design
For 2007, Honda puts innovative performance within the grasp of every sport rider with the groundbreaking new CBR600RR, a machine that vaporizes established boundaries in the 600cc class and creates performance standards heretofore unknown--on the street as well as at the track.
For fans of the sporting motorcycle, 2007 will long be fondly remembered as the advent of an epoch-making era. Beginning in 2007, racetracks around the world will reveal a new breed of MotoGP machines for the first time, the latest generation of smaller, lighter, more agile machines capable of astounding speeds. Truth be told, the average sportbike fan will never be allowed to sling a leg over such exotica, much less ever experience firsthand the sharpest of all blades of cutting-edge performance. But don't despair; the new CBR600RR brings cutting-edge credentials in its own right.
The 2007 CBR600RR doesn't merely extend the performance envelope in the class. It redefines what a middleweight sportbike should be: smaller, lighter, narrower, more powerful and amazingly agile compared to current class standards. Moreover, in keeping with a tradition Honda established with the introduction of the very first CBR600, the 2007 CBR600RR boasts features specifically aimed at enhancing the owner's street-riding experience--proof positive that a cutting-edge sport machine need not sacrifice comfort at the altar of narrow-focus racetrack demands.
This accomplishment did not originate solely from clean-sheet engineering. In keeping with HRC's MotoGP mission to create a smaller and lighter racer capable of outperforming the current designs, Honda's CBR600RR engineering team followed a parallel path, achieving a superior power-to-weight ratio with all its attendant benefits through lighter weight, more compact dimensions and a new aerodynamic design. Two critical specifications hint of the CBR600RR's dramatic redesign: Wheelbase has been reduced by a whopping 23mm, and dry weight dropped more than 16 pounds.
Engine, chassis, exhaust system, bodywork--everything is new in the 2007 CBR600RR, and all of it was shaped by the quest for a smaller, lighter and faster package. Normally, one would expect the latest racing technology to trickle down to the production street side over time, but here's a case of reverse timing: The CBR600RR will hit the streets before the new generation of MotoGP bikes fill their first grid.
First Stop: Reduced Weight
In planning the design of the 2007 CBR600RR, the first targeted goal was massive weight reduction. In a class where the lightest bikes are separated by only a few pounds, dropping more than 16 pounds from the CBR600RR required Honda engineers to rethink virtually every piece of the puzzle. A whole new engine features components that combine to reduce overall engine weight by 3.7 pounds, making it the lightest engine in its class. The new chassis weighs an astonishing 12.5 pounds less than the previous 600RR chassis. Even the CBR600RR's electronics contributed to the weight loss, paring a pound off the previous components. No part, however small, was overlooked in the process of trimming weight for the desired advantages in performance. In completing this mission, the net result is class-leading acceleration at all speeds, a freer-revving engine and remarkably responsive, smoother handling.
Make It Light, Make It Small
Amazing as these achievements may be, weight reduction figured into only half of the equation for 2007; Honda engineers also targeted drastic reductions in size. And so the heart of the CBR600RR, the engine, shrank an amazing 27.5mm in length compared to the 2006 model, making its front-to-rear (459.7mm) dimensions by far the smallest in the 600cc class. This new-think approach tightens the distance from the engine's crankshaft to the transmission output shaft by 1.2 inches (30.5mm), allowing Honda to have the shortest front-to-rear dimension in the 600cc class.
To accomplish this, the transmission main input shaft was relocated just slightly forward and upward when compared to the 2006 configuration. Given this extra bit of clearance, the transmission countershaft is now squeezed in much closer to the crankshaft in a more tightly triangulated configuration than before, which allows the reduction in engine size. This shortened engine length facilitates a drastic reduction in wheelbase compared to the previous-generation CBR600RR (which already had one of the shortest wheelbase figures in the class). The new bike places its axles 0.90 inch (23mm) closer together for a truly revolutionary wheelbase figure of 53.8 inches.
Changing the Chassis Paradigm
Given a substantially shorter wheelbase, conventional thinking would change the steering geometry to more conservative figures to add stability. Not so with the 2007 CBR600RR. In fact, the new machine has a steeper steering-head angle than ever before: 23.7 degrees from 24.0 degrees, while steering trail increased from 95.0mm to 97.7mm. So how did Honda get the stability required? In addition to a whole new frame, the CBR600RR features the next-generation Honda Electronic Steering Damper (HESD).
To create a super-agile yet stable sportbike with a profoundly confidence-
inspiring nature, Honda's engineers created a new generation of the Honda Electronic Steering Damper (HESD). Like the unit that first debuted on the CBR1000RR, this HESD helps maintain smoothly predictable high-speed handling while having remarkably little effect at slower speeds. However, this new version is less than half the size and more than 25 percent lighter (21.4 ounces vs. 29.1 ounces) than the original HESD design. Given such reduced dimensions, the CBR600RR's more compact HESD unit could be easily shrouded beneath the fuel tank cover, immediately behind the steering head, where it is mounted to the frame and connected to the upper triple clamp by an articulating arm that moves the unit's damping vane within its oil chamber.
As before, handlebar movement directly actuates this vane located within the unit's oil chamber. As the vane moves, it sends oil from one side of the chamber to the other through oil passageways regulated by an electronic solenoid. As vehicle speed and acceleration increase, the solenoid gradually constricts these oil passageways to effectively damp out sudden movements of the front fork and handlebars, such as might occur when encountering a large bump in a high-speed corner. As vehicle speed slows, the passageways gradually open, reducing the damping effect to virtually undetectable levels at parking-lot speeds.
In actual use, this new-generation electronically controlled steering damper offers an exceptional level of technological sophistication and seamless operation. Moreover, HESD allows the CBR600RR to achieve new levels of handling performance by incorporating steering-geometry settings and a shortened wheelbase that would otherwise prove unfeasible when viewed through the filter of past standards of design.
New Fine Die-Cast (FDC) Frame
The 2007 CBR600RR also incorporates next-generation Fine Die-Cast technology that allows the frame to become smaller and drastically lighter. This advanced manufacturing technique helps create an organically formed structure that offers an optimal balance of light weight and rigidity. In order to both reduce weight and enhance mass centralization, the number of component parts and welds used to build the frame dropped significantly. The 2006 CBR600 frame was comprised of 11 welded-up sections, while the new frame is made of only four larger castings. These four sections include a stout new steering head casting with a new, centrally located ram-air port, two main spars that wrap around the engine and a single rear pivot-mount section that incorporates an exceptionally rigid U-shaped cradle under the rear of the engine. While all sections were hollow-formed with approximately the same 2.5mm wall thickness as used in the 2006 frame, the new frame is more than 1.1 pounds lighter than the unit it replaces, as well as being stronger, slimmer and more compact.
Extraordinary reductions in front and rear mass play a major role in the new CBR600RR's improved mass centralization and cornering response. The smaller engine permits more effective positioning within the frame for optimal mass centralization and weight distribution. The engine's smaller fore-to-aft length makes it possible to shorten the CBR600RR's wheelbase by a remarkable 0.90 inch (from 54.7 inches to 53.8 inches) while simultaneously gaining swingarm length (to 22.55 inches), another MotoGP-inspired design that optimizes traction at the rear wheel. The chassis' shorter wheelbase also provides the opportunity to reposition the steering head, now situated 10mm (0.39 inch) farther forward than in the 2006 model, as measured from the crankshaft. This change increases steering leverage about the vehicle's rotating axis to produce sharper, more responsive handling.
Paring Engine Ounces
One of the attendant benefits of smaller engine proportions is the opportunity to pare weight from engine components, and Honda engineers took full advantage. The crankcase castings alone weigh approximately 2 pounds less than the previous cases, representing the largest portion of the engine's exceptional 4.4-pound weight reduction compared to the 2006 model. Other weight-reducing modifications include a new magnesium head cover (11.55 ounces lighter), redesigned nutless connecting rods, new single exhaust valve springs matched to smaller and lighter lifters, a smaller neodymium ACG magnet, a smaller and lighter clutch, and many other detail changes that contribute to the new engine's amazingly tidy configuration and lighter weight.
Stronger Performance to Boot
In the world of sporting motorcycles, smaller and lighter are always better, especially when combined with more power--and the 2007 CBR600RR does not disappoint in this department. Many of the new technologies developed for the CBR1000RR have been adapted to the new 600 engine, including modified intake- and exhaust-port shapes, smoother port walls, changes to the intakes' velocity stack lengths and taper, and enhancements to the ECU program governing the control of the two-stage PGM-DSFI fuel-injection system. The CBR600RR also boasts a new, lighter-weight stainless steel exhaust system equipped with an inline exhaust valve to tune exhaust pressure for maximum performance.
As a result, engine performance for 2007 is not only stronger throughout the powerband, but the power curve is more linear. The new engine now features a noticeably fatter torque curve between 7000 and 10,000 rpm, broadening the range of performance so riders of all levels can make better use of the muscle on tap. In addition, peak horsepower in the CBR600RR is significantly increased, and this output comes at 13,500 rpm, 500 rpm higher than the previous engine's peak.
Ram-Air Induction System
To aid the production of this newfound power, the 2007 CBR600RR now sports an impressively large air intake port built into the nose of the front cowl, precisely where the air stream hitting the fairing flows at its strongest. Modeled after the system developed for the World and AMA Superbike-championship-winning RC51, this new fresh-air port feeds directly through the new frame's open steering head casting and into the CBR600RR's larger-volume airbox. This new ram-air system provides a direct flow of cooler, dense air to the intake tracts, all the better for producing more power.
PGM-DSFI Dual Stage Fuel Injection System
Given this ample supply of cooler, dense air, the new CBR600RR incorporates Honda's race-proven two-stage PGM-DSFI system to ensure thorough fuel atomization and optimal cylinder charging at all engine speeds. One set of injectors installed at the entrance to the intake ports provides an ideal air/fuel mixture for quick starts and strong, smooth acceleration at low- to mid-range settings. At higher engine speeds, the system's second set of "showerhead" injectors installed in the roof of the airbox kicks in to deliver extra fuel to cool the high-volume air intake. These injectors also create a denser mixture that improves volumetric cylinder filling efficiency for stronger acceleration.
For 2007, the system's airbox has been increased in volume by 0.7 liter and the fuel feed lines have been simplified with new, lighter, moulded-plastic tubing and connectors replacing the previously used brazed-metal fuel lines. Also, a new intake-air control valve (IACV) smoothes engine response when the throttle is opened or closed by creating more gradual initial transitions in throttle settings.
New Pistons and Connecting Rods
The CBR600RR now features forged slipper-type aluminium pistons that are 3.5 percent lighter than before to reduce reciprocating weight. The pistons are also treated with a molybdenum shot-peening process that impregnates the surfaces of the piston skirts with a durable, low-friction coating, just like the treatment applied to the pistons in the CBR1000RR. The new CBR600RR also uses a higher compression ratio (12.2:1 from 12.0:1), and it now features a thinner lower oil ring to further reduce engine friction. The pistons are also cooled from underneath by new high-pressure oil jets built into the crankcase, which provide a stream of oil to the undersides of the pistons that effectively wicks away heat buildup. Also new to the CBR600RR are redesigned nutless connecting rods that are lighter for 2007. These rods use threaded bolts screwed directly into tapped holes in the rods to hold the endcaps in place. These lighter rods make an important contribution to reduced reciprocating weight for more responsive power and quicker acceleration.
New Knock Sensor
The 2007 CBR600RR also features a new knock sensor that maintains optimum spark advance throughout the entire rpm range while constantly monitoring combustion performance for signs of detonation. Should detonation be detected, the system automatically retards the spark advance just enough to eliminate the problem. Specially programmed to distinguish detonation from other engine noises, this system can even safely correct for the use of low-octane fuel (albeit with reduced performance), instantly retarding timing until any signs of detonation disappear, and then quickly advancing the timing again to a point just short of the knock zone to maintain optimal combustion characteristics at all engine speeds. Net effect: The CBR600RR's ignition timing settings are tuned for the highest performance levels without fear of inducing engine-damaging pre-ignition. Hence more power, but safely.
New Low-Lash Transmission
Revised transmission gear ratios take full advantage of the new engine's added performance and allowed the rear sprocket to be changed from 43 teeth to 42 teeth. Meanwhile, closer tolerances and redesigned components in the CBR600RR's transmission reduce the amount of gear lash felt during throttle transitions. This new transmission with undercut gear teeth also yields more positive engagement for smoother shifting action.
Form Follows Function
The new CBR600RR's stunningly innovative bodywork finds its origins in the wind tunnel. The design of the bodywork incorporates air-management principles derived from the wings and fins used on both fighter jets and Formula One race cars. The new shape more efficiently directs air around and through the CBR600RR's compact form while also giving visual cues to its aerodynamic function. The visible gap between the front upper cowl and the fairing's side cowls serves an important function: Because this section is divided into two parts, high-speed air resistance can be diverted into two smaller areas rather than influencing one large plane, thereby sharpening handling at higher speeds.
The shape of the front upper cowl is now more compact, with its nose and surrounding form repositioned 1.2 inches rearward and closer to the steering head compared to the 2006 model. The new lower cowl has also been made more compact, and it wraps more tightly around the exhaust headers. This design helps direct airflow for more effective cooling while visually emphasizing the CBR600RR's improved aerodynamics. This slimmer form also extends to the radiator, now 40mm narrower and 34.2mm taller. These compact proportions contribute to slippery aerodynamics while increasing cooling capacity.
The rear seat cowl is also significantly reduced in size and slimmed in shape. Combined with the shorter, more compact muffler and simplified lighting bracketry, this change helps reduce mass at the bike's extremities, contributing to more responsive handling.
Improved Riding Comfort
The handlebars have been raised 0.7 inch compared to the previous model to enhance rider comfort, while the handlebar-to-seat distance remains essentially the same as before. The CBR600RR's new proportions also allow a reshaped seat with deeper padding for added comfort, yet at no cost in seat height, which remains unchanged at 32.3 inches.
Premium Race-Ready Suspension Components
Up front, an impressive 41mm inverted Honda Multi-Action System (HMAS) cartridge-type fork provides smoothly responsive performance coupled with excellent rigidity and low unsprung weight. The fork offers full spring-preload, rebound and compression-damping adjustability, and 4.7 inches of travel. Integrated into the CBR600RR's rigid but lightweight swingarm is the Honda Unit Pro-Link rear suspension system pioneered on the race-winning RC211V MotoGP racer. Its advanced design isolates the frame from shocks and stresses generated by conventional rear suspension systems, especially under aggressive riding and racing conditions. This system also eliminates the need for extra frame reinforcement to counter those stresses, thus allowing a frame that's lighter than more conventional frames while also freeing up space to permit the lower, mid-chassis positioning of the fuel tank--another large contribution to mass centralization and superior riding control. An integrated HMAS rear damper features a built-in remote gas reservoir and likewise offers full spring-preload, rebound and compression-damping adjustability with 5.1 inches of travel to provide smoothly progressive control on both road and track. For 2007, a new lighter, extruded linkage system replaces the previous linkage setup, which was forged aluminium. The linkage geometry has been changed to match changes in the 2007 frame, but the linkage ratio is still the same as on the 2006 version. Also, the suspension's spring and damping rates front and rear have been altered to complement the new frame and engine characteristics.
Top-Shelf Wheels and Brakes
Another factor that plays an important role in achieving the CBR600RR's lighter weight and more centralized mass are the triple-spoke cast-aluminium wheels, which feature compact hubs for an ultra-lightweight design that minimizes unsprung weight. A pair of high-performance radial-mount four-piston brake calipers and 310mm rotors provides superlative stopping power up front with excellent feel at the lever. The CBR600RR now features the vertically oriented radial front-brake master cylinder system first introduced on the CBR1000RR. This system provides straight-line actuation and a longer lever for additional leverage plus improved power and feel with a distinct reduction in effort. At the rear end, a compact and highly responsive single-piston caliper stops a 220mm disc between sintered-metal pads.
New Compact Instrument Panel
The new CBR600RR also sports a totally new and more compact instrument panel design, with its tachometer featuring larger, more easily distinguished odd numbers and smaller even numbers for easy recognition and differentiation. As before, a large LCD panel provides a high-visibility readout of vehicle speed, odometer, tripmeters, fuel gauge and clock. Brilliant ISO-marked indicator lights are positioned around the perimeter of the panel. When the ignition key is switched on, the instrument panel also comes alive with an eye-catching startup routine that flashes the indicators and sweeps the tachometer needle.
2007 CBR600RR: A Breed Apart
Thanks to a direct infusion of MotoGP-inspired innovations, the 2007 Honda CBR600RR will literally stand out from the crowd as it immediately erects new class standards for performance in all areas. You'll not find such compact engine or chassis dimensions in any other street-going machine. But this new bike isn't about specifications and numbers. Like the best MotoGP racers, it's all about how well the machine integrates with the rider, and also how well it works on both the street and the track. The new CBR600RR balances the best of both worlds while elevating the bar to new class levels for concept, execution and outright performance.