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CBR1000RR Engine Technology
The CBR(R)1000RR boasts a truly world-class powerplant, an all-new liquid-cooled 998cc inline four-cylinder engine carefully designed to also enhance
handling. Begin by comparing the overall silhouette of the new 1000 and the CBR954RR, and immediately you can see there's no comparison; the CBR1000RR boasts significantly smaller, more compact dimensions. There are blatantly
obvious changes, such as relocating the oil filter away from the front of the engine to save space. And high-tech tricks such as designing a new, slimmer and lighter ACG with neodymium magnets to help keep case width especially
narrow. But Honda's commitment to mass centralization in this new-generation Superbike permeates through and through every cubic centimeter of the engine.
For example, at the very heart of the CBR1000RR, we find a
compact 75mm bore size contributing significantly to the engine's narrow proportions. Engine stroke measures 56.5mm--a combination also selected specifically for its ability to generate loads of torque along with plenty of
top-end horsepower.
Making it Light
Strong and durable forged aluminum slipper pistons coupled to nutless connecting rods feature less reciprocating mass to produce a quicker-revving engine. In addition, the piston skirts have
been impregnated with molybdenum to create a friction-reducing surface, an innovative treatment both tougher and longer lasting than the LUB coating Honda(R) used previously. More than a surface coating, this process literally
shoots particles of pure, low-friction molybdenum into the skirts of the piston with such high force and temperature they become embedded into the surface of the aluminum with a chemical reaction that bonds the material
together.
These pistons run through aluminum composite cylinder sleeves high-pressure formed from sintered aluminum powder impregnated with ceramic and graphite for improved wear resistance and superior heat
dissipation. And for the first time in a street bike engine design, the CBR1000RR cylinder block incorporates a semi-closed deck that positively secures the tops of the cylinder bores to the outer walls of the block with
cast-in bridges for increased rigidity and consistency in cylinder bore shape under all conditions.
To further reduce reciprocating mass, the CBR1000RR features nutless connecting rods with end caps held in place by
bolts that thread directly into tapped holes in the rods. This design shaves approximately 50 grams out of these critical engine components to reduce mechanical loads and also improve engine response and acceleration.
The DOHC cylinder head employs four valves per cylinder, 29mm intake and 24mm exhaust. These valve head diameters match those from the 954, but the stems of the new valves have been slimmed from 4.5mm to 4.0mm for lighter
weight and reduced friction. This weight reduction also allows the use of lighter valve springs, for quick and precise valve actuation. Compared to the 954, included valve angles are slightly flatter (23.5 degrees vs. 25.0) to
open up the combustion chamber for more efficient burning, and intake ports were raised to create a straighter path for the incoming fuel charge. The CBR1000RR features shim-under-bucket valve adjustment for high-rpm
durability; engine redline is set at 11,650 rpm. To keep the engine spinning smoothly even at such elevated speeds, the RR features a light but efficient balancer shaft mounted close to the crankshaft to maximize mass
centralization.
Programmed Dual Stage Fuel Injection
To feed this big engine, Honda engineers lifted another page from the RC211V formula and installed Programmed Dual Stage Fuel Injection (PGM-DSFI). As its name
implies, DSFI employs a pair of injectors for each cylinder.
This dual-injector system eliminates a significant compromise inherent in older single-injector setups. In the past, if low-end engine response was desired,
the fuel injectors were mounted close to the intake ports. On the other hand, if maximum power was desired, the injectors had to be mounted father away from the intakes--a direct conflict with the practice of positioning the
injectors for best response. Honda's engineers resolved the compromise by employing dual injectors to meet both objectives.
First, a set of all-new Denso injectors has been mounted in the venturis of the large 44mm
machined aluminum throttle bodies. An entirely new manufacturing process endows these fourth-generation injectors with a radial array of 12 holes that produce a wider, more diffused output. As a result, this more finely
atomized spray covers a wider area and mixes 20 percent more efficiently with the intake air, which results in more efficient combustion. In addition, new, dramatically lighter needle bearings allow the injectors to respond to
electric signals 30 percent faster than the previous generation--an amazingly short response time of 1/1000th second. In addition, these new-generation injector bodies also weigh 25 percent less than the previous units.
To ensure a constant flow of fuel at higher engine speeds to produce maximum power, the second set of 12-hole injectors rests in the top of the air box, directly above the velocity stacks of each throttle body. This second bank
of injectors come into play at engine speeds of 5500 rpm and higher.
As these showerhead-style injectors spray a finely atomized fuel charge into the intake areas, this blast cools the air/fuel mixture, thereby creating
a denser charge that produces more power. Together, these dual injectors solve the classic injector dilemma, delivering stellar throttle response while also pumping out exemplary top-end power.
A sophisticated 32-bit
Electronic Control Unit with dual 3-D injection maps for each cylinder manages the fuel injection system, and also handles the ignition and emissions systems. In addition, the ECU incorporates the control systems for the
ram-air intake system, exhaust valve and the CBR1000RR's innovative electrohydraulic steering damper. Amazingly enough, for all of its high-powered processing capability, this new-generation ECU is small enough to fit in the
palm of your hand.
Cold air intake for the CBR1000RR is controlled by a two-stage system, which includes the main ram-air duct located below the bottom triple clamp and above the new large-capacity radiator, plus a
smaller dual-intake sub-duct system. At low engine speeds, air flows into the sub-duct system through two doors, one located on each side of the larger intake tract. At higher engine speeds, a vacuum-operated system closes the
doors to the sub-duct system while simultaneously opening a door to the main ram-air duct, thereby creating a high-pressure flow of cold, dense air for a dramatic increase in midrange and high-speed power. New high-flow
cylindrical air filter elements reside within the 8.35-liter air box, which is hidden away under the front portion of the faux fuel tank cover.
Exhaust Tuning Made Simple and Light
On the exhaust side of the engine,
a brand-new servo-controlled system actuates a next-generation valve located within the four-into-two-into-one steel and titanium center-up exhaust system. This cable-actuated stainless steel butterfly valve resides just
downstream of the collector and is operated by a servomotor that receives control signals from the central ECU. As a bonus, this new system is a whopping 770 grams lighter than the system used in the CBR954RR.
By tuning
exhaust pulses and back-pressure at specific engine speeds, this system significantly improves power output and engine response at all engine speeds without the added noise. As this tunable exhaust system works in conjunction
with the Dual Stage Fuel Injection system--with air flow managed by a new ram-air setup--the CBR1000RR power plant has become a model of engine tuning flexibility. As a result, this world-class machine does it all: it churns
out massive amounts of low-end torque, packs a wallop in the midrange, and then caps it all off with genuine Superbike-class top-end power.
Cassette Gearbox
Another industry-leading feature gracing the CBR1000RR
takes its roots squarely from the racetrack: a cassette-type close-ratio six-speed transmission. Thanks to the easy access afforded by a cassette gearbox, the 1000RR will definitely deliver an advantage to racers who need to
match gearing to different racetracks and under varying conditions. To gain access to the gearbox you simply remove the right side crankcase cover, and the clutch assembly, shift forks and drum can be removed as an entire
assembly. To cope with its additional power, the clutch diameter now measures 140mm, up from 125mm in the 954, and clutch actuation now occurs through a hydraulic system.
With an eye fixed firmly on the racetrack,
Honda's engineers designed a radiator for the CBR1000RR that dwarfs the unit affixed to the 954, boasting 211 square inches compared to 127 square inches. This increased size raises cooling capacity 41.5 percent, from 26kW to
36.8kW, and the fan size has also grown from 171mm in diameter to 191mm. Whether you find yourself on the starting line at your local racetrack or stuck in stop-and-go city traffic, you'll be sure to appreciate this extra
cooling capacity.
How was it possible to incorporate such a large radiator? Again, it was part of a holistic design from the very beginning. Setting the cylinder block in a relatively upright position creates more room
up front, and that space was enhanced by repositioning the oil filter from its familiar up-front position to a spot on the right side of the engine--a design elegant in its simplicity.
Another example of
racetrack-oriented engineering can be found in the lightweight magnesium oil pan. By employing special high-temperature magnesium in place of aluminum, Honda's engineers could save a full 375 grams. This special material also
provides better structural resistance to deformation at extremely high temperatures, for more reliable sealing. As an added weight-saving measure, the 1000RR's head cover is also made of magnesium.
By completely
rethinking the architecture of the venerable inline four, Honda engineers have created an engine that gives a nod to the past and accelerates hard into the future, bringing world-class liter bike performance and race-proven
technology to the production line in 2004.
Torrance, Calif. 02/01/2004
CBR1000RR Development
Consider this: Unlike the majority of new-model motorcycles, the lineage of the 2004 Honda(R) CBR(R)1000RR doesn't really reach into the past. True, Honda
has crafted many other large-displacement transverse inline four-cylinder motorcycles in prior seasons, a rich tradition established in 1969 by the landmark CB750K0. But the new RR doesn't follow in the tire prints of those
forerunners; it carries over no hardware from past machines.
A quick scan of the CBR1000RR's features confirms its newness. The compact 998cc in-line four is a completely fresh design, with unique bore and stroke
dimensions, race-inspired cassette-type six-speed gearbox, all-new ECU-controlled ram-air system, dual-stage fuel injection, and center-up exhaust featuring a new computer-controlled butterfly valve. The chassis is likewise all
new, including an organic-style aluminum frame composed of Gravity Die-Cast main sections and Fine Die-Cast steering head structure, inverted fork, Unit Pro-Link rear suspension, radial-mounted front brakes, and a
centrally-located fuel tank hidden under a faux cover.
The roots of the CBR1000RR design stretch across the present and future, tapping wholesale into the cutting-edge technology from within Honda's world-dominating
RC211V MotoGP racing program. For the past two years, the RC211V has stood head and shoulders above all would-be challengers, the uncontested champion in the rarified air of MotoGP racing. And that's where the heart of the
CBR1000RR lies.
One of the main advantages of the RC211V is its ability to put power down early in the corners. While generating upwards of 200 horsepower from modern MotoGP machines is a relatively easy engineering
task, managing that power, making the bike ridable and seeing a resultant drop in lap times is another matter altogether. The RC211V's long wheelbase, coupled with a lengthy swingarm and Unit Pro-Link(R) rear suspension, are
credited for much of the bike's ability to start accelerating earlier than other machines when exiting corners, and it is here the CBR1000RR is most closely aligned to the RC211V's design philosophy.
Harnessing
acceleration and creating a balanced, rider-friendly package in a modern liter bike--especially one destined to be transformed into a racing Superbike with significantly more power than the production model--presented CBR1000RR
engineers with much the same challenges as those facing the RC211V's engineers. And the CBR1000RR team has taken the same engineering approach, a complex puzzle of component placement that begins at the business end of the
CBR1000RR.
With the longest swingarm in the literbike class, the CBR1000RR reflects a Honda handling philosophy proven by the RC211V: a longer swingarm acts as a longer lever arm in the rear suspension for superior
traction under acceleration and more progressive suspension action. Substantially longer than the corresponding unit on the CBR954RR--585mm compared to 551mm--the CBR1000RR's 34mm-longer swingarm now makes up 41.6 percent of
its total wheelbase. The CBR1000RR's wheelbase has also increased, taping out at 1405mm (55.3 inches), a 5mm increase over the 954.
Providing room for a longer swingarm required massive changes to the engine
architecture, another reason the CBR1000RR power plant shares nothing with the 954. Shortening the engine compared to the 954 meant rejecting the conventional in-line layout. Instead, engineers positioned the CBR1000RR's
crankshaft, main shaft and countershaft in a triangulated configuration, with the countershaft located below the main shaft, dramatically shortening the engine front to back, and moving the swingarm pivot closer to the
crankshaft.
Positioning this compact engine farther forward in the chassis also increases front-end weight bias, an effective method of making high-powered liter bikes less wheelie prone under hard acceleration. This
approach, however, also provides very little space between the engine and front wheel for a large radiator. Engineers solved this problem by giving the RR a modest cylinder incline of 28 degrees, and moving the oil filter from
its frontal placement on the 954 to the right side of the 1000RR engine. This allows the RR's center-up exhaust system to tuck closely to the engine, opening the space required for a massive MotoGP-style curved radiator with 40
percent more cooling capacity than the 954's unit--a key to making big horsepower with high durability.
Look closely at the 1000RR's engine, and you'll see that much was designed specifically with an eye toward handling
as well as horsepower and torque. Why? Because the power plant represents a large percentage of a motorcycle's mass, the engine must be configured to assist the handling process, not hinder it. For decades, Honda has championed
the concept of mass centralization, that is, concentrating the component masses as close to the motorcycle's center as possible. The CBR1000RR elevates that concept to a higher plane.
Renewed Emphasis on Mass Centralization
As a rider initiates a turn and then leans into the turn, the motorcycle rotates around its roll axis, an imaginary horizontal line running fore and aft through the center of mass of
the bike and its rider. To create a motorcycle that responds quickly and smoothly to rider input, the major masses need to be placed as close to the bike's roll axis as possible. As an illustration in the opposite extreme,
tightrope walkers are fond of carrying a long, weighted pole specifically because such a device slows down input and motion, which helps them remain stable while walking on that long, thin line.
Honda engine designers
paid special attention to making the CBR1000RR power plant an extremely compact package to enhance mass centralization and reduce the roll polar moment, while yielding other benefits as well. Specifically, consider the RR's
bore and stroke. While some engines employ ever-more oversquare dimensions, Honda employed a relatively modest 75mm bore with a 56.5mm stroke to derive a displacement of 998cc. This choice yields a remarkably narrow engine fit
into a commensurately narrower chassis, all the better for increased mass centralization and improved ground clearance as well.
Other measures taken to enhance mass centralization in the CBR1000RR include positioning
the starter motor and drive gear on the right side of the engine, which also creates a narrower engine profile for added ground clearance. The 1000RR incorporates a balancer shaft to virtually eliminate secondary engine
vibration, and with an eye toward mass centralization it too has been positioned close to the engine's center of gravity.
Just as they did with the RC211V, Honda engineers looked at the CBR1000RR as an organic whole for
centralizing mass. Placing other major masses--fuel and rider--closer to the roll axis results in a motorcycle that reacts more quickly and smoothly to control inputs at the handlebars. Like the RC211V and the CBR600RR, the
CBR1000RR fuel tank shares space under a faux tank cover with a forward-mounted air box, thanks to the Unit Pro-Link rear suspension system.
The Unit Pro-Link design provides a wealth of benefits. To begin with, the
shock is contained entirely within the swingarm, and the shock is positioned lower than in a conventional design. Both contribute to mass centralization, in part by giving the centrally mounted fuel tank room to extend
downward. Because the shock is contained within the swingarm and does not require a top mount on the frame, the bulk of the 4.8-gallon tank can be positioned down low between the frame rails, close to the centerline of the
machine. Two other benefits result from the RR's fuel placement; the mass of the fuel load has less effect on handling, thereby facilitating quick directional changes; and, because the fuel tank is shorter, the CBR1000RR rider
sits closer to the steering head compared to the 954.
To achieve quicker handling, Honda engineers also lightened as many pieces as possible that are far from the center of mass. That gave rise to the RR's compact
Line-Beam headlights, with their high-illumination three-piece reflectors; slim-line LED taillight; single-piston rear brake system that's lighter than that of the 954; an analog/digital fully electronic instrument panel that's
one of the lightest and slimmest ever mounted on a street bike; plus a host of other changes.
Never before have the sum of the parts of a production street machine added up to such a greater overall whole. Perhaps
that's the greatest legacy the CBR1000RR has inherited from its RC211V MotoGP racing roots.
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