Sharpened Scalpel: Honda CBR954RR road test

Honda's venerable open-class CBR hits the gym yet again to emerge as the stronger, lighter CBR954RR

Honda steps up its CBR with the stronger, lighter CBR954RRKevin Wing

"The CBR must be a more versatile motorcycle that still has top performance, but is easier for the average person to ride on the street," remarked Tadao Baba, the now-famous project leader for Honda's open-class CBR-RR series since its inception back in 1993. "We feel the [Guess which brand he mentioned? --Ed.] is more of a racetrack-only, experts-only machine."

Since taking the world by storm with the original 1993 CBR900RR, Honda has watched the open-class sportbike landscape change drastically in the last four years. Power outputs have jumped dramatically, with chassis and suspension performance rising at a similar pace. Today's big-bore sportbikes are faster and more nimble--in both track and street environments--than ever before.

Despite all this excitement about horsepower and speed, Honda has always prided itself on the versatility of its sportbikes. By versatile, we're talking about user-friendliness; the ability of a motorcycle to accommodate riders of varying degrees of skill. Hondas have always had the reputation of highly polished packages that reflect countless hours of R&D.;

The debut of the Yamaha YZF-R1 in 1998, however, forced Baba and Honda to ratchet up their development program and introduce the 929 two years earlier than planned, in 2000. And now, with Suzuki's GSX-R1000 having turned the sportbike world on its ear in 2001, along with a redesigned R1 (see AT's First Ride, page 54) making its appearance this year, it's pretty obvious that subtle refinements and new paint weren't going to cut it for 2002. So the big CBR receives a slew of substantial upgrades, the most obvious of which is an increase in displacement from 929 to 954cc. User-friendly or not, Honda is looking to back up its new "Performance First" sales slogan. It seems the open-class performance wars are getting just as hot as the 600cc category.

The Honda CBR954RRKevin Wing

LOSE WEIGHT/GAIN POWER NOW,ASK ME HOW! Rather than take the prohibitively expensive route of designing and producing an all-new engine in their quest for more power (and performance), Baba and the Honda engineers took the usual path of trimming weight while squeezing some more ponies from the same basic engine. The problem is that the 929RR was already pretty lean (it was the lightest of our BOTY open-class contestants), with an engine design that reflected that same philosophy (not a whole lot of room to increase displacement).

A lighter, more powerful CBR.Kevin Wing

This meant that the engine gets its displacement increase strictly through a 1mm larger bore. And even that was a push; there is now only 1.5mm between each aluminum composite cylinder sleeve. Compression ratio was raised a smidge from 11.3:1 to 11.5:1 via new piston assemblies that, despite being larger, are six percent lighter. The pistons are starting to resemble Formula One pieces, with almost no skirt to speak of; the wristpins are now essentially the same size as 600F4i units. Cam timing duration was increased three degrees for both intake and exhaust, with a corresponding three degrees more overlap for better breathing at high rpm. Single exhaust valve springs replace the previous dual units for a total of 2.5 ounces less unsprung valve train weight.

Fuel injection throttle bodies are now 42mm (up from 40mm), with new injectors featuring 12 laser-drilled jet holes (from the previous four) for finer fuel atomization; the second-generation PGM-FI's ECU is also much more powerful and quicker-computing. Airbox capacity is the same, but now breathes through inlets that snake over the frame rails resembling ram-air ducts, but aren't; there are no intakes on the front fairing.With such a lean design, weight pared off the motor is now measured in grams. The new starter motor using "neodium" magnets is much smaller, and is 400 grams lighter (nearly a pound, for you non-metric heads). Computer-aided design helped shave off over 160 grams from the crankshaft and engine cases. The muffler is now completely constructed out of titanium (except for the outer covers), shedding another 440 grams. In sum, the new engine assembly weighs two pounds less than last year.

Redesigned and reshaped, the 954's profile is slimmer between the rider's knees.Kevin Wing

The CBR's chassis also underwent extensive changes, aimed at weight reduction and/or improving overall rigidity. Modifications to the steering head casting thickness and the D-shaped lower frame brace increase torsional rigidity 8.6 percent (while actually decreasing lateral rigidity 3.6 percent--more on that later), with tapered roller bearings now used in the steering head. Lighter, redesigned rear castings utilize repositioned rear subframe mounts, which, combined with the reshaped fuel tank (10mm shorter and flatter), help slim the 954's profile between the rider's knees.

The swingarm is all-new, utilizing technology gleaned from HRC's racebikes. Instead of the previous unit's extruded aluminum beams welded to a large pivot casting, the majority of the new swingarm uses large, stamped aluminum sheet box-sections that are welded together with a smaller pivot casting. Although physically larger than the previous swingarm, the new component scales in 340 grams lighter. The rear shock spring is 250 grams lighter (thinner wire, same spring rate), while the shock itself sports a more linear damping rate for better high-speed bump absorption.

The same 330mm discs are present on the 954's front end, but the brake calipers have been subtly redesigned with smaller trailing pistons. Performance is improved substantially, with far better feel than the 929's already good blinders.Kevin Wing
The 954's exhaust canister is now all titanium, except for the outer cover and end caps, which are the only pieces on the entire exhaust not constructed out of the ultra-lightweight metal. Note the race stand button bosses welded to the bottom of the swingarm.Kevin Wing

Although the same 330mm front brake discs are used, other portions of the brake system have been slightly redesigned for better feel. The master cylinder uses a smaller piston for more brake system pressure at a given lever pressure, while each caliper's trailing pistons are smaller (32mm vs. 34mm). Both wheels are all-new, employing more compact hub and spoke castings to trim an additional six ounces of unsprung weight from each wheel.

Those black plastic runners leading from the airbox to the front fairing appear to be ram-air ducts, but they're not. The intake duct hidden underneath ends halfway, and simply breathes air from inside the front fairing.Kevin Wing

Bodywork also received a substantial makeover, with a more aggressive, angular appearance. The windscreen is 15mm taller for better protection (an accessory 50mm-taller unit is available), and the taillight now uses LED-type illumination like the Yamaha R6.

It didn't seem likely, but Honda was able to trim six pounds off the new CBR954RR, making it still the class lightweight (unless the new R1 suddenly goes anorexic) at 429 pounds wet.

Easing the pressure on a rider's wrists as well as offering more leverage with its more upright ergos, the 954 also boasts more legroom than the GSX-R1000 to boot.Kevin Wing

A CHASSIS WITH LESS RIGIDITY?
Yep, you read it right. The new CBR954RR chassis is actually less rigid than the 929 unit in certain aspects. Although the 954RR main frame (including the D-shaped lower frame brace) is 8.6 percent more rigid torsionally than the 929RR's unit, it is actually 3.6 percent less rigid laterally. The new swingarm may look beefy, but it is in fact 25 percent less rigid laterally, and 25.6 percent less rigid torsionally than the older component (actually, this was mostly achieved through the use of a slightly thinner pivot shaft).

But before you get all frothed up and think the CBR954RR has a wet noodle for a chassis, we suggest you read the "Look Ma, No Pivot" sidebar in our CBR929RR test in the June 2000 issue. In a nutshell, the concept is this: when a motorcycle is leaned over in a corner, bump forces are fed from the ground nearly perpendicular into the chassis--angles too great for the suspension to handle. That leaves the tires and chassis with the job of dealing with irregular pavement, but today's radials have stiff sidewalls to cope with the severe sideloads they encounter during hard cornering.

Don't try to look for spring preload rings on the Showa fork's adjuster cap. You'll need to remember how many turns out from full stiff you're at in order to determine preload. In their quest to pare every gram possible from the CBR, Honda changed to the spring preload to an internal mechanism.Kevin Wing

This means you can actually have a chassis that is too stiff. In 1993, Wayne Rainey's Yamaha YZR500 GP bike came equipped with a super-rigid frame, but the triple world champion struggled with tire chatter and other handling problems until he switched to a privateer ROC chassis. Engineers have found that a certain amount of flex is desirable in a motorcycle's frame and swingarm for improved feel and handling.

ROAD KILL
Since the 954 retains the 929's riding position (although the shorter tank has you sitting up a tiny bit more), and the suspension feels the same at lower speeds, the new CBR's city manners are pretty much the same. Easy cold morning warm-ups, responsive throttle response, lithe, light handling and crisp, one-finger-application brakes allow you to shred traffic with ease. The 954's added midrange punch and acceleration, however, add a new dimension to its urban weapons; combined with its light weight, the 954 literally leaps away from stoplights. We also appreciated the redesigned gear engagement dogs in the transmission, which made gearshifts much cleaner and easier.

In order to shed a little weight and impart some "HRC trickness" into the swingarm, Honda constructed much of the 954's unit (left) from pressed aluminum sheets instead of the previous extruded beams (right).Kevin Wing

The bike's highway manners are substantially improved due to the beefier powerplant. The taller windscreen helps wind protection noticeably, and vibration is the same as before--minimal, except for a little tingle between 4500 and 5000 rpm. Roll-ons, however, are another story; the light weight and extra midrange power mean the Honda responds much better to throttle inputs in top gear at 60 mph, allowing you to pass a string of offending four-wheelers with ease.

However, while we're talking about highway manners, we should bring up our one major gripe with the new 954: its poor gas mileage. Even with only moderate applications of full throttle, the low fuel light always came on around the 120-mile mark; this meant you only had about 25 miles left on the 0.8 gallon reserve. A 145-mile range on a modern inline-four isn't exactly what we'd call exemplary fuel efficiency.

As long as the gas stations aren't too far away, sampling the fruits of Baba's and the Honda engineers' labor in the twisty bits is where the real payoff begins. The 954 retains the 929's incredibly light and flickable, yet razor-sharp steering abilities, allowing you to carve the tighter canyons like no other open-class machine. Mid-corner steering corrections take little more than a thought process to accomplish. Make sure the Michelin Pilot Sports are up to operating temp (which takes a few turns), and the precise front end feedback works with the scalpel-like steering to give you the confidence to charge into corners later and deeper. As the pace heats up, the 954's ultra-lithe handling and hyper-responsiveness requires smoothness in steering inputs, however, overly rough or aggressive body movements can upset the chassis a bit.

Yes, the CBR's trademark flip-up passenger seat trunk is still there, but it's somewhat smaller in capacity, with about a third less space to work with now.Kevin Wing

The 954's midrange boost is a major plus in these environs, with a much more substantial spread of power between 6000 and 9500 rpm. Yes, you still have to rev the CBR harder than the competition to get some serious propulsion going, but it's not as much work as before; the motor's quicker-revving nature lets you carry a lower rpm through certain corners without suffering a penalty in drive off the turn. Top-end power feels a tad bit stronger than the 929, a fact born out by the dyno chart. Not that it was really lacking in that department--although there is the question of a bike with the initials GSX-R....

We should note here that the 954's brake updates are another added bonus, providing fantastic feedback and fade-free power. We didn't really have any complaints about the 929's binders, but the 954 brakes' feel and progressiveness reminded us that there is always room for improvement. They let you expend less energy dealing with hard braking, so that you can work on other riding tasks, like higher corner entrance speeds.

Baba-san says the CBR is aimed more at the street rider, but little details like this rear ride-height adjuster on the rear shock's top mount, and the bosses welded onto the bottom of the swingarm for race stand buttons, belie that premise. Like the Suzuki GSX-Rs, you'll need to find different-thickness washers in order to adjust the ride height.Kevin Wing

The Honda's overall handling is excellent, although it still exhibits a bit of the same "busy" feel in rough corners as the 929. While nothing bad enough to cause worry or rob you of confidence, it does remind you that you're riding a light, short-wheelbase bike with fairly radical steering geometry (23.8 degrees rake, 97mm trail). Softening the suspension enough to keep it from feeling busy ended up allowing too much chassis pitch during acceleration and braking. Again, we feel this is due to the bike's highly centralized mass; it's a lot easier to twirl a stick with its weight kept in the center, rather than out toward the ends.

This may be the reason that Baba and the Honda engineers decided to increase the lateral flexibility of the chassis. In order to counteract the lack of outlying weight toward each end (which adds inertia to resist movement), they needed a way to keep midcorner bumps from upsetting the chassis. Although the 954 still has a slightly busy feel, it is noticeably less nervous over sharp midcorner bumps at full lean, especially considering the fact that it lacks a steering damper. And yet the chassis never exhibited any handling maladies associated with excessive flexibility, even while charging around Las Vegas Speedway with Michelin Pilot Race DOT tires mounted at the press introduction.

The 954's piston on the right may be larger in diameter, but it's six percent lighter than the 929 piston on the left, along with a wristpin that is the same size as the 600F4i unit. Note the rather miniscule side skirt on the 954 piston.Kevin Wing

LAST CALL
With the open class suddenly becoming the focus of development in the past few years, it's tempting for a manufacturer to just inject a big dose of horsepower into the current model and proclaim success. Honda is one factory, however, that has generated success by careful, methodical updates to its models when necessary. The CBR954RR is a reflection of this philosophy: By bolstering the 929's strong points, Honda has created one of the sharpest, most maneuverable liter-class rocketships to ever hit the pavement, while still retaining the user-friendliness of its predecessor.

It should be interesting to see how it stacks up against the competition this year....

Honda CBR954RR

Honda CBR954RRKevin Wing

Suggested retail price: $10,599

ENGINE
•Type: Liquid-cooled, transverse, inline, 4-stroke four
•Valve arrangement: DOHC, 4 valves/cyl. shim-under-bucket adjustment, 16,000 mile intervals
•Displacement: 954cc
•Bore x stroke: 75.0 x 54.0mm
•Compression ratio: 11.5:1
•Carburetion: Keihin PGM-FI, 42mm throttle bodies
•Transmission: 6-speed

**CHASSIS **
•Front suspension: 43mm inverted cartridge fork, 4.3 in. travel; adjustments for spring preload, compression & rebound damping
•Rear suspension: Single shock absorber, 5.3 in. travel; adjustments for spring preload, compression and rebound damping
•Front brake: 2, four-piston calipers, 330mm discs
•Rear brake: two-piston caliper, 220mm disc
•Front wheel: 3.50 x 17 in.; cast-alloy
•Rear wheel: 6.00 x 17 in.; cast alloy
•Front tire: 120/70-ZR17 Michelin Pilot Sport E
•Rear tire: 190/50-ZR17 Michelin Pilot Sport E
•Rake/trail: 23.8 deg./3.8 in. (97mm)
•Wheelbase: 54.9 in. (1395mm)
•Seat height: 32.3 in. (820mm)
•Fuel capacity: 4.8 gal. (18L)
•Weight: 429 lbs. (195kg ) wet, 400 lbs. (182kg) dry
•Instruments: Tachometer, digital LCD with speedometer, dual tripmeters, clock, coolant temperature; lights for neutral, high beam, turn signals, low oil pressure, low fuel level

PERFORMANCE
•Fuel consumption: 28-32 mpg, 30 mpg avg.
•Top speed: N/A
•Quarter-mile: 10.26 sec. @ 137.57 mph
•Roll-ons: 60-80mph/ 2.80 sec., 80-100mph/ 2.82 sec.

Horsepower and Torque ChartKevin Wing

CBR Timeline -- The 954's family tree

1993-'94

’93–’94Kevin Wing

When it was first introduced, the 1993 Honda CBR900RR set a staggering precedent for light weight that some manufacturers are still attempting to match. At 453 pounds with a full tank of gas, the 900 was just four pounds heavier than Honda's own CBR600F2, and a mind numbing 76 pounds lighter than the next-lightest open-class machine at the time, the Yamaha FZR1000. And although it finished a tick behind the FZR in SR's first open-class shootout, we raved that, "The 900 felt like a 600 from the seat but looked like a superbike from the dragstrip's timing tower." Minor changes to the '94 model included an improved shift drum to cure notchy shifting, and steadier mirrors.

1995

’95Kevin Wing

In a move to refine the CBR's handling traits over bumpy pavement, the '95 model's suspension was upgraded with revised spring and damping rates, and a compression adjuster was added to the front fork. More aggressive bodywork incorporated a "cut reflector" design headlight and fewer of the CBR's unique fairing holes. Slimmer and firmer footpegs were patterned after the RC45, and a shift linkage replaced the original model's backward pedal. A new instrument panel included an electronic speedometer that measured speed from the countershaft sprocket. The only engine change in 1995 was the replacement of the aluminum valve cover with a magnesium piece.

1996-'97

’96–’97Kevin Wing

In order to achieve "optimized balance of rigidity," Honda significantly altered the '96 CBR's chassis and suspension. The frame and swingarm were fabricated from larger, thinner-walled extrusions for reduced torsional rigidity. The fork and shock internals were re-designed, and the swingarm pivot raised by 5mm. Revised ergonomics brought the bars 10mm higher and swept back five degrees more than earlier models, along with a slimmer gas tank. Engine updates included a bump in displacement to 918cc via a 1mm bore increase, slightly higher compression, a curved radiator, larger muffler, extra clutch plates, smaller alternator, and the addition of a throttle position sensor. New graphics were the only change for 1997.

1998-'99

’98–’99Kevin Wing

Continuing "subtle refinements" in the CBR's chassis saw frame stiffness closer to the original model's, revised suspension internals, and 5mm less triple clamp offset (an almost universal aftermarket upgrade to previous models). New brake calipers acted on larger front discs, the fairing was re-shaped and raised footpegs subtly changed ergonomics again. Eighty percent of the engine's internals were all-new to reduce weight and minimize friction; other updates included redesigned combustion chambers and porting, aluminum composite cylinders, new pistons, a smaller and lighter clutch pack, revised gearbox ratios, larger radiator, and a new stainless steel exhaust header.

2000-'01

’00–’01Kevin Wing

A major revision for the open-class Honda resulted in the CBR929RR, aimed squarely for Yamaha's R1--which took Honda's original CBR concept further. A completely new engine incorporated fuel injection, more oversquare cylinder dimensions, larger valves set at a narrower included angle, lighter internals, and an all-titanium, HTEV-equipped exhaust system. The "pivotless" chassis had the swingarm mounted to the engine cases but incorporated a brace underneath the engine. Updated suspension and brakes included an inverted front fork and huge 330mm front discs; and, finally, the CBR's trademark 16-inch front wheel was ditched for a more common 17-inch hoop.

SR Opinions

Make no mistake, the new 954RR rocks. Baba-san's newest creation is nearly as flickable as the F4i, and the motor's added midrange punch lets the new Honda squirt through the tighter stuff like no other open-classer; a pilot on any of the competition's bikes will be working a little harder to keep the same pace. The slightly revamped brakes are some of the best I've ever experienced on a production motorcycle--excellent feel and power, with good progressiveness and modulation.

The 954RR's chassis can get a little excitable in the fast, bumpy sections, however. A by-product of the chassis' highly agile geometry numbers and weight distribution, the CBR requires a bit more attention to the front end when the going gets speedy and rough. And that can be taxing after awhile, both physically and mentally.

And then there's that little ol' question of 130 horsepower vs. 143 horsepower--can the CBR squirt out of the way before Tyrannosaurus GSX-Rex gets into his stride? We shall see....And then --KentKunitsugu

I think Honda has done the right thing by shying away from an all-out horsepower war with Suzuki and the GSX-R1000. When the 929 was introduced, it seemed to me as if it was the only open-classer that delivered big horsepower in a 600-sized package and that adding 15 horsepower would only upset that balance. The 954 has that extra spunk in the midrange though, right where you notice it most. This makes it seem a lot quicker than the 929, and the bottom-end injection has been cleaned up a whole bunch also. With the smaller tank, the new bike has even more of that compact 600 feel.

That's what I like about the 954, but the added friskiness comes with a penalty. I find in many ways the bike is almost too responsive, requiring a lot of concentration to ride at even a relaxed pace. Hair-trigger throttle (with a touch of RC51-itis over bumps), ultra-quick steering, and stiff suspension make it more of a chore to ride than the 929 and other open-classers. I'd make some direct comparisons to the GSX-R1000, but prying that thing away from Kent so I could actually ride it (rather than just swap tires) is like taking a puppy's favorite bone.

I wouldn't be sweating it if I owned a 929, but the 954 is a big-enough step forward that the big-bore shootout is going to be a lot tougher to call than people think. Can't wait.--Andrew Trevitt