2006 Honda CBR1000RR development
The 2004 season witnessed the introduction of a truly innovative machine: Honda's CBR®1000RR. The big RR represented a landmark break from past sport bikes; rather than following in lockstep with its predecessors, it instead drew from the present state-of-the-art and hurtled headlong into the future. By tapping wholesale into the cutting-edge technology gleaned from within the company's ultra-high-tech MotoGP racing program, this new design unveiled a whole new era of big-bore supersports machine. Indeed, the basic DNA of the CBR1000RR sprang forth from the incredible RC211V®, a technological wonder that incorporated exotic and ground-breaking chassis architecture to accomplish its single purpose in life: winning races.
Like the MotoGP racer, the CBR1000RR design utilized an innovative long-swingarm, weight-forward configuration that allowed the machine to get more power to the ground sooner when exiting corners--thereby creating a remarkably well-balanced and rider-friendly package that simultaneously wielded the kind of awe-inspiring power that only a modern-day liter-bike could generate. The 1000RR's credentials seemed never-ending: gravity die-cast aluminum frame, extraordinarily compact high-output engine with Dual Sequential Fuel Injection (DSFI), Unit Pro-LinkTM rear suspension, radial-mount front brakes, and the unique Honda Electronic Steering Damper (HESD).
A never-ending quest for performance
Innovative as the new CBR1000RR appeared, its 2004 rollout provided scarcely a pause for Honda's engineers because life in the 1000cc sportbike class revolves around a single, relentless quest: more performance. This unquenchable drive for additional development and more performance continued virtually unabated. So now, only two years later, 2006 brings the next evolutionary step in the life of the 1000RR. To that end, the 2006 CBR1000RR offers advancements in every parameter, with more power, better handling and less weight, thanks to the following changes:
- New intake and exhaust porting
- Higher compression ratio
- Revised cam timing
- More intake valve lift
- Double springs for the intake valves
- Higher redline
- Larger rear sprocket
- New exhaust system
- New chassis geometry
- Larger 320mm front brake discs
- Revised front suspension
- Revised rear suspension with new linkage ratios
- New lighter swingarm
Power is where you find it
In the ultra-competitive liter-class sportbike wars there's no time to rest, no free lunch, no easy path to improvement. Which is to say the CBR1000RR's improvement in power output was achieved not with any single change, but rather with a collection of carefully developed modifications that add up to a significant boost in performance.
To start, the cylinder-head's intake and exhaust ports were refined in shape and size to yield a straighter path for higher flow--and a resulting significant improvement in power feel. The reduced volume in the combustion chamber provides a distinct increase in the compression ratio, from 11.9:1 to 12.2:1, although this alteration was achieved in a slightly unusual fashion. Rather than change only the shape of the combustion chamber proper, Honda's engineers also reshaped the surfaces of the intake valves that face each combustion chamber; shallower dished-out areas essentially add material to the chamber to reduce volume and help raise the compression ratio. To nullify any weight gain to the intake valves, each valve had a corresponding amount of material removed on the opposite side of the valve head, in the area near where the valves rest in their seats.
Other performance-up measures include new valve timing and more lift (from 8.9mm to 9.1mm) on the intake side to help boost power, and a new double-spring design for the intake valves replaces the single-spring setup previously used--all the better for enhanced power output and reliable operation at higher engine speeds. Specifically, torque now peaks at 10,000 rpm, 1500 revs higher than before, and engine redline increases from 11,650 rpm to 12,200 rpm with the 2006 model. In conjunction with a larger rear sprocket (from 41 to 42 teeth) these changes enhance acceleration while top speed can remain unchanged. Usually, gains made in a larger rear sprocket's sharper acceleration must be paid back in reduced top speeds, but this new engine's taller redline and stronger high-end power output maintain the CBR's high top-speed ceiling for performance.
When details count
To build in even greater durability during extended high-speed operation, a new crankshaft made of a stronger steel alloy provides enhanced stiffness and strength to meet the demands of high performance without adding extra weight. In addition, the camshafts have been lightened via thinner shaft wall thicknesses to trim weight from the drivetrain. The net result of all these changes is an approximate 3% increase in peak power output, with fully 75% of the improvement credited to the changes in the cylinder head and porting. These refinements also help achieve an improved power-to-weight ratio, resulting in sharper acceleration and noticeably stronger rush through the entire powerband.
A new, more simplified internal design for the electronic control unit (ECU) results in a modest reduction in its weight, making yet another small but significant contribution to the overall weight loss. A new magnesium ACG cover further contributes to reduced engine and overall machine weight; previously, only the head cover and oil pan had been constructed of magnesium.
Other detail improvements abound. A revised internal crankcase venting system reduces power loss due to crankcase pressurization. A lighter cam chain tensioner slices weight from the engine, as does a new cooling system impeller, which also improves flow for enhanced engine cooling and reduced heat-induced power loss. A larger-diameter thrust washer in the clutch provides more surface area and a wider needle bearing in the clutch basket adds strength and durability. The result is greater durability and smoother clutch engagement action as well. The shift drum shaft has been changed to reduce weight, and the transmission engagement dogs are undercut more for more positive shifting and less driveline lash.
On the intake side, the internal shape of the ram-air intake ducts have been altered to improve airflow and the grill covering the intake system now features a larger grid pattern for enhanced flow. The upper "showerhead" fuel injectors in the DSFI system now feature a revised spray pattern for greater efficiency as well.
Refining the elegant
The CBR1000RR burst onto the streets and Superbike racing scene in 2004 with an all-new gravity die-cast aluminum frame and advanced Unit Pro-Link rear suspension layout taken directly from Honda's famed RC211V MotoGP racer. Cradling the potent engine is a stressed-member diamond configuration that contributes to the big CBR's exceptional handling stability. This frame is light weight and has a relatively simple, organic form.
The 1000RR chassis and frame receive a host of refinements that add up to a significant improvement in overall handling ease and smoother response to rider input. First, the inverted, fully adjustable cartridge-type front fork now features fork springs made of a different material with an increased rate, and more spring preload is used. The steering head's caster angle is reduced slightly--a quarter of a degree--from 23 degrees, 45 minutes to 23 degrees, 25 minutes. Together with a reduction in trail from 102mm to 100mm (3.9 inches), these alterations help sharpen steering response and overall handling. In another change to the chassis, the swingarm is reduced fractionally in length by 4mm. Overall these chassis changes have decreased the CBR1000RR's wheelbase from 55.6 inches to 55.3 inches for quicker steering.
In back, the single-shock Unit Pro-Link suspension system--patterned after RC211V MotoGP technology--now incorporates a more supple spring rate (from last year's 12.0 kg/mm to 11.5 kg/mm) and a new linkage system that yields less rising rate. As before, the rear damper boasts full adjustability for spring pre-load, compression and rebound damping, and a lighter aluminum spring pre-load adjuster ring now replaces the steel piece used on the previous iteration.
New front brake rotors: larger and lighter
The CBR1000RR's superb radial-mount front disc brakes increase in diameter from 310mm to 320mm in 2006, and this change yields a readily apparent increase in braking power and a greatly enhanced feel. In order to minimize unsprung weight, the thickness of the rotors is reduced from 5mm to 4.5mm, resulting in a total weight reduction of 300g. Also lightening the chassis unsprung weight is a new smaller and lighter rear-brake caliper. And the rear wheel and sprocket are now fitted with a new set of dampers that better absorb the shocks of quick clutch operation and sudden jolts of power to driveline during hard acceleration and deceleration.
Lighter Exhaust System
To further minimize weight, even the 4-into-2-into-1 titanium and stainless steel exhaust system was revised in construction, trimming weight from the pipes, the servo-controlled exhaust valve--which increased in diameter from 45mm to 48mm--and from the center-up silencer located under the seat. This latter reduction not only shaves weight, it also contributes to the CBR1000RR's enhanced mass centralization for excellent handling traits.
For 2006, the CBR1000RR also sports a next-generation look thanks to all-new bodywork that projects a decidedly aggressive impression. The front and side cowls boast a sleeker, more curvaceous and more assertive look that still maintains strong bloodline ties to its MotoGP racing predecessor. Detailed changes include a more pronounced indent in the front cowl and redesign for the shape of the RR's distinctive slim-line headlights which combine to project a more aggressive forward visage. The fairing's new side cowls also feature more open and rounded lines to lighten and accentuate the bike's aerodynamic look while also complementing its high-speed handling. The CBR1000RR's sleek and slim seat cowl follow the bike's aerodynamic lines, and give its rider optimal maneuvering ease and comfort. Although the seat itself appears unchanged in shape and thickness, the 2006 version has a revised foam material to enhance rider comfort. Unseen below, the seat railing also changed shape to reduce weight. Under the tail's lower surface, a cleanly integrated slim-line LED taillight--now made with a heat-resistant polycarbonate lens that supersedes the previous acrylic item--hovers over the center-up exhaust system's prominent exit port, which features a newly restyled look.
Enhanced power. Less weight. And sparkling new looks to boot. In 2006 the state-of-the-art in liter-class sport bikes has advanced in giant steps once again. Thanks to the power of Honda engineering and the new CBR1000RR.