Honda CBR600RR 

Racetrack Serious


Honda CBR600RR Launch
Barber Motorsports Park
February 2007

The sportbike market in general, and the 600cc sportbike in particular, has become increasingly bi-polar since the late 1990s. It started with the track-biased testing of the moto-media and was reinforced by the increased profile of road racing and the ever-rising popularity of track days. These forces combined to demand that the manufacturers deliver sport bikes with the hard emphasis on sport. Of course, as the emphasis goes to ‘sport’ the streetability of the bikes is compromised. Ergonomics designed for twenty minute sessions of high-speed athletic track riding are brutal for any sort of real-world riding. Engines designed to top out dynamometer comparison tests often suffer from lean spots in portions of the powerband which are never used on the track but always used on the street as the fuel injection curves are tweaked to pass emission tests.

 


Suitable for exit ramps as well.

Honda has always been the company that resisted this push to the sharp edge. Honda sportbikes were always firmly based in the street riding experience. This strategy was quite sensible because the company's research told them that only 5% of CBR purchasers ever saw the painted curbs of a racetrack. For the last six or seven years the presence of a Honda on a 600cc Supersport class grid was basically restricted to a few sponsered entries in the AMA and some misguided novices who converted their streetbikes for track use. In track-based testing (such as we do at Roadracing World) the CBRs usually did not fare well due to their street-riding bias and often placed low in 600cc comparisons. Although Honda would often send delegations around to various magazines questioning the results of comparisons and complaining about the results, the company had the last laugh as, despite the comparisons, the CBR remained the best-selling 600cc sportbike in the country.

Indulging in a little corporate anthropomorphizing: Honda is a proud company that does not like to lose anything, even apparently irrelevant magazine comparisons. The company's most recent attempt to rectify this situation was the 2005 CBR600RR. Unfortunately Honda engineers had underestimated how far the other three Japanese manufacturers were willing to go with their 600s and although the Honda posted good numbers, it came in too heavy and cumbersome to compete with its sportier competition. This was painfully apparent despite Honda’s ceaseless attempts to link the pedestrian CBR with the exotic RC211V and bludgeon the pundits into declaring it the best 600.

No one ever likes to admit a mistake (particularly a proud company) but Honda introduced the 2007 CBR600RR with more discretion, less hype and a much better product. The 2007 CBR600RR is, in fact, the first CBR that I (personally) have ever liked. With its clean-sheet, all-new design it closes the track performance gap against its competitors while still maintaining its eminent streetability for 95% of its future riders.


Carbon touches on the gas tank and tail section are portions of Honda’s aftermarket catalog.


First Impressions

The morning riding sessions at Barber Motorsports Park were under cloudy skies with periodic mist gathering on my visor. The track was still drying from some early morning rain showers. Conveniently, it was very similar weather to when I tested the 2005 bike two years before at Buttonwillow.

The 2005 bike did not feel like a natural sportbike to me. The riding position was awkwardly far forward, giving me the sense that I was in front of the center of gravity of the bike instead of matching it. It was possible to ride it fast but it took some faith and a lot of acclimatizing.

The new bike feels neutral from the first leg over. The bike fits well with a narrower profile, a comfy seat, and handlebars and footpegs that are aggressive enough for the track but not excruciating at lower speeds. Giving the bike the pre-ride bounce and wiggle reveals smooth and effectively damped forks and the electronic steering damper allows for unexpectedly light steering at low speeds. The side-to-side shake reveals the dropped weight and the narrower feel between the legs.

Honda doesn’t typically skimp on its four-stroke technology and this bike does not disappoint - it is powerful and smooth. The dual-stage fuel injection and ample computing and sensor power allow the new CBR600RR to pull hard all through the rev range but also fuel smoothly at steady low speeds. On the track or cruising around the pits there were no harsh on-off throttle transitions.


The 2007 throttle bodies (top) are both smaller, lighter and
incorporate the intake-air control valve for smoother response.
 

The lower weight is felt from brake markers to the turn-in to the apex and from throttle-on to the next shift point. The de rigueur radial master cylinder provides ample fade-free power for a very fast track-day pace. As the lighter weight of the bike is less taxing on the brake system and the master cylinder is improving the rider’s leverage ratio on the pads, one can more easily modulate the brakes for trail braking.

The bike turns with lower effort and holds a tight line but in a neutral fashion. It settles rapidly onto a line and carves easily. Even over Barber’s deceptive cresting hills the Honda could still find the front-wheel traction to grip and turn without running wide. The surface at Barber is quite smooth and uniform to begin with but the couple of spots on the track that typically induce chatter or roughness in a racebike were not able to upset the CBR. The suspension specification is not dramatically different from the 2005; either the internal calibration, the new frame or the reduced weight allows for a much improved feel for the tires on the new CBR. Whereas the older bikes always felt a little mushy and distant, this one feels much more connected to the road. It is not as busy as a GSX-R600 or YZF-R6 but it cuts a good balance between good rider feedback and over stimulation.


With the exhaust taking up much of the undercarriage the rear brake reservoir had to move
to the outside. Racetrack riding did not yield a hot right calf but August city traffic most likely will.

Throttle pick up is smooth and powerful for a 600. Like most middleweights one needs to flog the engine mercilessly to get the best out of a lap but dropping the bike lower in the powerband was not immediately punished with a bogged drive. For instance, if one were to get distracted thinking about the ennui of post-industrial America versus the carpe diem attitude of the Italians and so, lost in thought, one only drops a single gear into the Spider Turn instead of two gears, the exit drive is not so bad, so that one might just go ahead and live with it instead of catching the dreaded exit downshift.


The Air Intake Control Valve gives the rider perfect
on-off throttle response for moments like these.

The steering damper is electronically activated with the speed of the bike. This allowed the Honda to steer lightly and precisely at low speeds without the muddy feeling of a steering damper, yet wheelieing the bike across the rises at Barber never induced any wobbles.


The great-great grandfather of the CBR came out to pit lane at Barber to see how junior was
holding up. This is when racers were real men, not like us sissies today with our
radial tires, brakes, suspension, frames, and computer controlled engines.

The transmission is tight and accurate. Thrashing around Barber through three sets of tires (one set of OE and two sets of GPs) did not result in a single missed shift or questionable gear choice moment. The bike is not fitted with a slipper clutch but the manual clutch allows for sideways entrances to the low speed turns. At one point in the technical presentations one Honda representative suggested that the intake air control valve helped to ameliorate the need for a slipper clutch. Although the IACV might have some of the responsibility for the bike’s excellent fueling the CBR felt quite conventional in terms of downshift-induced back torque.

Beauty is, of course, in the eye of the beholder but I think this CBR is the first one where they got the styling correct. Older CBRs either looked too fishy, too chinless or too jowly; this one looks aggressive without looking cartoony and finally has a face to match the legs.

This is very adept track bike in stock trim even with the OE tires. It will probably be the best street bike of the middleweight class with its impeccable low speed manners and reasonable ergonomics. Buyers of this CBR should at least take it to a track event once to run up Honda’s statistics as well as enjoying the full capacities of the machine. With its new aptitude and Honda’s resurrected contingency programs this bike might start showing up in the hands of racers other than a handful of novices and AMA riders.


What Changed


The 2007 Honda CBR600RR uses a centrally located gas tank to lower and centralize weight.
A deep sump oil pan keeps the oil away from the crank and makes room for the pipe down
the left side of the bike. Every component is tucked into the aerodynamic or lean angle
profile. Note the short engine, high transmission shafts and forward-placed swingarm
pivot which no longer runs though the crankcases. Handlebars are now 10mm higher.
 

Through the late 1980s and most of the 1990s Honda ruled the middleweight class. This started with the 397-pound CBR in 1987 and continued to the 405-pound F3 in 1995. The 1997 GSX-R600, followed by the YZF-R6, bumped the CBR to the back of the grids in terms of weight, handling and performance. With middleweights currently weighing in with feather weights in the low 350s this Honda claims an almost unbelievable 345-pound dry weight. That is a massive 16-pound reduction from the 2005 model. This was apparently not done through chicanery as the Honda reps at Barber weighed the 2006 with a full tank versus the 2007 and found that the wet weight of the 2006 model was 430 pounds while the wet weight for the 2007 model was 412 pounds. This, of course, was not a cheap thing to do and Honda is passing the costs on to the final consumer. The 2005 CBR was the most expensive middleweight in its day at $8799 and the 2007 is coming in at a pricey $9499. The fact that the U.S. dollar is in the gutter right now is not helping those of us with an affinity for products produced overseas.


Despite the vestigial nature of the windshield
the coverage was surprisingly effective.
 

The development goals for the 2007 CBR were almost the standard recipe for sport bike development: Lighter, better handling, and more power. The difference with the CBR is that Honda engineers did not aim to increase the peak power but instead focused on smoothing and boosting the mid-range. To accomplish this Honda replaced the frame, the swingarm, the engine, the fuel injection system, the exhaust and portions of the brakes. This new package was clothed in a sleeker set of bodywork.

The frame, reminiscent of the YZF-R6 frame, is four large fine-die-cast pieces welded together. This construction incorporates RC51-style air induction straight through the steering head and more tightly wraps around a shrunken powerplant. The frame weighs 1.1 pounds less that its 11-piece predecessor. The smaller engine and more compact frame allowed Honda engineers to reduce the wheelbase of the bike 0.9-inches from 54.7 to 53.8 while adding traction-inducing length to the swingarm which now pivots 5mm higher in the frame.

The triple-adjustable inverted forks run 41mm stanchion tubes while the rear suspension carries forward the Unit Pro-link system. The Unit Pro-Link in theory isolates the shock action forces allowing for a lighter frame construction and freeing up space for the centrally located fuel tank. The 2007 sports a lighter extruded linkage replacing the forged piece on the older design. The linkage geometry has changed to match changes in the frame design but the actual linkage ratios are constant.


Mirrors are typically not taped for street use.

Both wheels are of a lighter design. The front carries 310mm rotors matched to Tokico radial-mounted calipers. These are now activated with a radial master cylinder with those inherent improvements in feel and leverage ratios. The rear carries the standard 220mm rear disc.

The front end is damped by an innovative steering damper design carried down from the CBR1000RR. The Honda Electronic Steering Damper is centrally mounted on the top of frame and attached to the top triple tree with a short linkage and two heim joints. This second generation HESD is 25% lighter and 50% more compact than the original design. Handlebar action rotates a vane in the middle of the damper; the vane pumps oil from one chamber to another but a speed-controlled solenoid decreases the size of the orifice as road speed increases. This allows the bike to have little or no steering damper at low speeds and increased damping at high speeds, just the way you want it. The electronic steering damper gave the Honda engineers the confidence to sharpen the steering geometry a touch to a rake of 23.7 degrees with 97.7mm (3.85 inches) of trail.

Air is directed into the new airbox through straight air vents formed by the front upper fairing stay and ducted through the steering head of the frame. This results in an almost straight shot to the larger airbox from the highest pressure portion of the front fairing.



It’s a straight shot to the air filter through the front of the fairing.

The airbox feeds the dual-stage throttle bodies. One set of injectors is mounted in the traditional throttle body location. These are optimized for low and medium engine speeds. A second set of injectors is mounted in the velocity stack shower position in the lid of the airbox; this set of injectors is used in high engine demand situations. The throttle bodies have been lightened, shrunk, and fitted with an intake air control valve which is designed to create more gradual initial transitions from closed to open throttle positions. An anti-knock sensor has been included into the ECU circuit to prevent engine damage with lower octane or high load conditions. Iridium spark plugs have been specified to boost performance.

The I4 16-valve engine of the CBR is all new with smaller, lighter and more compact internals. The transmission shafts have been repositioned to create a shorter engine; the crankshaft to countershaft distance has been reduced 30.5mm. The transmission gears have been manufactured with greater undercuts (to make more positive shifts and increase the durability of the dogs) and with tighter tolerances to reduce the amount of lash. The pistons are lighter and the skirts are treated with a low friction coating. The exhaust valves are now closed with a single spring to reduce weight. The alternator has a lighter and smaller neodymium magnet rotor. The clutch remains without a slipper function but the outer basket is smaller and lighter despite the inclusion of an additional outer band of material to increase its stiffness and durability. The engine is cooled with a narrower, more compact and more efficient radiator.


The black low friction coating on the 2007 pistons gives an idea
of how detailed Honda is getting to eek out small performance gains.


The muffler now has titanium internals to reduce the weight of the under seat unit and the exhaust system features a valve controlled by the ECU to improve performance or sneak the bike through government noise tests depending on whose version you believe.


A central air intake allows for sleeker cheeks resulting in the best-looking CBR ever.
The seat is even surprisingly comfortable.
 

Honda has also jumped on the “factory accessory” bandwagon and is selling a bunch of carbon do-dads to tart up your bike. The CBRs will be available in black, red and black, pearl white, and ultra blue in your local dealers in March of 2007 for $9499.

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