The CBR600RR's front suspension was targeted as the main area from which to find improved levels of handling. Honda's development engineers noted in testing that there has been a slight tendency (a result of improvements in both bike and tyre performance, plus much more efficient brakes) for the front suspension on recent Supersports bikes to dive quickly when the brakes are applied, a phenomenon which has a destabilising effect on control.
Improved damping function was key for the new CBR600RR, so a fully adjustable Showa Big Piston inverted front fork, with an exceptionally rigid 41mm diameter inner tube, has been used. Compared with the previous fork, the larger diameter piston results in a 3.5 times larger pressure-bearing area. This ensures that precise damping force is generated without delay from the initial phase, resulting in greater smoothness, a more comfortable ride, and greater stability when braking hard. Transient damping force characteristics are also improved. Riding on ordinary roads is more comfortable than before and when the bike is taken to the limit on the racetrack, there's an improved sense of connection with the tarmac when braking. Adjusting the rebound and compression settings has been made easier by consolidating the functions for both on the upper part of the front fork.
The CBR600RR's Unit Pro-Link rear suspension uses no shock top mount on the frame, and is a system unique to Honda. The shock mounts to the upper part of the swingarm and the lower link, effectively operating independently of swingarm movement. This stabilises behaviour under hard cornering and delivers superb traction and turning ability, plus improved shock absorption and much more consistent damping.
Continued development of the Unit ProLink system – refinement of the pressure-bearing surfaces in the piston and optimisation of valve rigidity – has resulted in much better low speed performance and greater feedback in the initial phase of operation, giving superb stability and controllability. The swingarm itself employs an "eye-shaped" cross-section and is manufactured using conventional cast aluminium for the pivot, pressed aluminium for the right-hand section and extruded aluminium tubing for the left-hand section. This has resulted in a lightweight component with an exquisite rigidity balance.
Receiving constant input from Honda's race programme, the CBR600RR's frame is constructed from twin tubes of diecast aluminium. A mass-centralisation process for the new model has resulted in the sections that are furthest away from the bike's centre of gravity being made lighter. This has made for more agile handling and sharper responsiveness and has taken turning ability and cornering speed up to the next level. Rake is set at 23° with trail of 96.3mm; wheelbase is 1,375mm and kerb weight 196kg (with electronic Combined ABS).
Both lightweight cast aluminium wheels feature the same 12spoke design used on the CBR1000RR. The load from braking, acceleration and cornering comes in many directions, and increasing the number of spokes spreads forces more evenly; combined with the Showa Big Piston Fork's improved road-adherence, the rider has a much greater sense of control, and feel, for front tyre grip.
As standard the CBR600RR's powerful braking setup uses the well-proven setup of twin 310mm discs with radially mounted opposed-piston four-pot calipers, and a lightweight single-piston caliper and 220mm disc at the rear. Sintered pads all round deliver effective power with linear control, and the radial mounts (the bolts securing the caliper are oriented forwards, not toward the axle) ensure much greater rigidity and even pressure across the whole pad. Greater braking efficiency and control is helped by use of a radial front brake master cylinder.
The CBR600RR has HESD (Honda Electronic Steering Damper) with optimal damping force constantly maintained by the ECU. Speed and throttle aperture status are detected by sensors and data sent to the ECU; at low speed the ECU fully opens the main valve inside the damper to reduce damping and make the handling lighter. When the bike is travelling at high speeds or accelerating the ECU closes the main valve increasing damping, to control interference from the road surface.
The styling of the new CBR600RR has a functional beauty that mirrors that of the race machine that inspired it – Honda's RC213V. The sleek, flowing fairing houses twin line-beam headlights; they're embedded deep within it, to concentrate mass, and also help direct airflow to the ramair duct. The screen, as on the RC213V is small and the tail unit mirrors that of the MotoGP machine. The fuel tank cover is shaped to allow the rider to move freely and grip it with arms and knees.
Its aerodynamic package also draws heavily on Honda's MotoGP machines. The result is 6.5% less drag than the previous model in a normal riding position, and 5% less when prone. The ability of the rider to redirect the road-ready CBR600RR while cornering is unmatched; these aerodynamic developments were looped back to the MotoGP engineers, showing how close the relationship between track and road is. engineers, showing how close the relationship between track and road is.
The CBR600RR's extremely compact 599cc, liquid cooled DOHC 16valve inline four-
cylinder power plant makes a great contribution to the bike's superb handling. Featuring a compression ratio of 12.2:1, it produces 88kW @ 13,500rpm, with torque of 66Nm @ 11,250rpm. In this stage of the engine's development improved power and torque were not the focus; instead, throttle response and feel across the entire rev-range were targeted.
The DAIS (Direct Air Induction System) smoothly channels a large volume of air directly through the intake situated in the middle of the front fairing (the area subjected to the greatest air pressure) and into the airbox via the steering head duct. The large polypropylene and fibreglass intake port extension that bridges the gap between the steering head and the engine also supports the front fairing and headlights, saving weight. Intake noise has been reduced by 3dB overall, without losing the satisfying howl familiar to CBR600RR riders.
New ECU mapping upgrades the PGM-DSFI (Programmed Dual Sequential Fuel Injection System) to optimise power and torque output characteristics. The PGM-DSFI also controls the large volume of air that enters the DAIS air duct and the fuel injected by the injectors, supplying the optimal mix across all rpm ranges.
Embedded in the ECU is a map designed to achieve optimal combustion in ordinary rpm ranges. There are two injectors to each cylinder; up to a certain level of rpm only the lower injector operates, but when the throttle is more than 25% open and the engine's operating at more than 4,800rpm, the upper injector comes into play. Efficient combustion and a razor-sharp throttle response is the result.
The IACV (Intake Air Control Valve) attached to the throttle has a new control map. Designed originally to stabilise rpm when idling and improve starting characteristics, its function has been expanded to cover all rpm ranges. The IACV aperture is finely controlled in accordance with rpm and optimises air intake volumes when the throttle is slightly open.
It also improves combustion ratios in the high-rpm and low-load ranges. As a result stable combustion is maintained when decelerating or when accelerating after decelerating.
Furthermore, the combined effect of the ECU programs, plus the air injection system and large capacity catalyser is to deliver a strong environmental performance.
Electronic Combined ABS
In June 2008, Honda announced the world's first "electronic Combined ABS" for production motorcycles, available on both the CBR600RR and CBR1000RR Fireblade in 2009. It remains unique, and has been used and further developed through two high profile racing series: the IDM German national championship (won in 2010 by Karl Muggeridge on an electronic Combined ABS equipped CBR1000RR), and the World Endurance Championship (in which electronic Combined ABS was used for the last two races of 2011, and throughout the 2012 season).
The system works as follows: input from the brake lever is recognised by a series of pressure sensors which are connected to an ECU. The ECU assesses front and rear wheel speed and, using this information, translates the lever pressure to power units which operate the front and rear brakes. Hydraulic pressure is then applied by these power units to the brake calipers, delivering the optimal braking force for every situation without locking.
All the expected ABS and CBS functions are provided – the prevention of wheel lock and the distribution of braking force between front and rear brakes – but the ultrafine precise control of the "brake-by-wire" system means that vehicle vibration and pitching are minimized, so that the bike remains in a normal, neutral position under braking. Brake "pulse" is also eliminated, and, overall, sport riding performance is uninterrupted cornering feel remains the same and controllability is enhanced.
Further features and benefits of the system include:
Adjusted rear brake operation when foot pedal applied
When the rear brake pedal is applied, the interval before the front wheel hydraulic brake control kicks in is set longer than in the mechanically controlled CBS. When the rear brake is applied gently, it operates without the front which enables the subtle application of just the rear brake to stabilise the bike when riding on winding roads, etc.
Natural activation of ABS
As well as detecting the slip ratio of the front and rear wheels, the electronic Combined ABS also detects the pressure with which the brakes are being applied, which translates into more precise brake force control. Because it is a 'brake-by-wire' system, there is no kick back on the lever or pedal, which means ABS can cut in more smoothly. As a result, ABS can be activated quickly without interfering with the rider's control over the brakes.
Natural lever feel
The stroke simulator allows a natural lever feel and response to the 'brake-by-wire' system. The stroke simulator is housed inside the valve unit; thanks to the characteristics of the flexible materials used it delivers a lever feel no different from that of a conventional brake system.
Centralisation of mass
In order to concentrate the mass of the electronic Combined ABS, system components are positioned around the machine's centre of gravity. By adding only lightweight sensors to the suspension increases in unsprung weight are kept to a minimum.