Honda CBR 900RR Fireblade

Dedicated to sweaty palms and fevered dreams of back-road fancy, Honda's take-no-prisoners CBR900RR is still the closest thing to a street-legal race bike you can buy.

Deep in their hard-core heart of hearts, every bevel-booted adrenaline addict knows one bit of wisdom: The surest route to pure twisty-road fulfillment is a race bike with headlights and a license plate. Strip it of all but the barest of street-going formalities. Arm it with brick-wall brakes, triple-digit horsepower, a chassis as rigid as 60s Soviet foreign policy and synaptic steering response. Roll it on big, sticky tires and make it weigh next to nothing.

The thinly disguised racer wouldn't hold you back. With limits far beyond your own, it would not only tell you exactly how good a rider you are, but would help you become a better rider. It would be the most fun you could have with your leathers on.

Well, the folks at Honda know what you're thinking. They understand clearly what legions of flinty-eyed sport-bike pilots have lusted after all along: a lightweight, missile-quick, heart-attack-serious sporting weapon or, in Honda shorthand, a CBR900RR.

In simple English, this is a big-bore sport bike reduced to its simplest form. No blinding displays of technological fireworks cloaked in marketing-department smoke and mirrors here. From the beginning, the basic design logic behind Honda's most focused CBR hinged on the simple fact that a lighter sport bike is a better sport bike. That's powerful logic when measured against the sheer mass of the CBR900RR's liter-class competitors.

Judged solely against the meticulously calibrated Motorcyclist scales, the 457-pound CBR has no peer in liter-bike land. That's 457 pounds, 25 pounds less than Ducati's svelte new 888 S.P.O. and just 3 more than Honda's own CBR600F2. And there, in a lightweight nutshell, is the secret to the 900RR's success: middleweight mass pushed by open-class muscle.

Aside from its shocking black, yellow and purple paint scheme (Honda offers two slightly milder color options), the list of changes for the '94 double-R is short and is comprised solely of a redesigned shift drum that Honda says offers smoother progress through the six-speed gearbox. That's it. Surprised? Don't be. When you've got an open-classer that handles like a 600, weighs only a few pounds more and offers top-shelf componentry throughout, you don't mess with it. And Honda hasn't.

Roll the 900 onto the scale and its weight advantage over the competition is instantly clear. Suzuki's GSXR1100 pioneered the low-mass open-class approach in 1986, though it has ballooned to 571 pounds in new-for-'93 liquid-cooled trim; that's 114 pounds more than the CBR. Yamaha's 533-pound FZR1000 pushes the needle on our scales 76 pounds farther than the Honda. And a fully fueled ZX-11 Kawasaki is a shocking 144 pounds porkier.

But simply making it light wasn't enough. Honda engineers wanted to move as much weight as possible away from the extremities of the motorcycle to sharpen its reactions even further. The process is called mass centralization, a bit of physics Honda has been using quietly for years, though never so meticulously as on the RR. Flip back to "The Mass-Centralization Solution" in our May '92 issue if you missed the full story. In a nutshell, everything a rider asks the machine to do becomes easier as the heavier bits migrate toward the center of the machine. If a part couldn't be positioned ideally during development, it was made as light as possible. The tiny 8 amp-hour battery, plastic headlight lenses and aluminum muffler canister are perfect examples of this.

Comparing the 900RR power plant to that of the CBR600F2 shows just how successful Honda engineers were in shaving weight. Though no parts swapping is possible, both share the same basic engine configuration. The RR's 893cc, 16-valve four is just 13mm taller than the engine pushing its 600cc sibling and just 50mm wider. And at 142 pounds, the 120-horsepower heart of the 900 is only 13 pounds heavier.

Driving the cam chain from the right side of the crankshaft rather than from the center helps keep the crank narrow—a crucial dimension for quick-flick turning. Touches like a tight, 32-degree included valve angle, asymmetrical intake runners and a tiny but powerful alternator driven off the left side of the crank all add up to the most compact liter-class four-stroke power source available.

The motor itself is a relatively long-stroke design, with bore and stroke numbers of 70mm by 58mm. These high piston-speed dimensions limit the engine's redline to just 11,000 rpm, though the design does allow the cylinder bank—which is cast as an integral part of the upper crankcase assembly—to be narrow and compact. Everything from carb sizing to cam timing is focused on creating a free-revving power source capable of cranking out accessible, upper mid-range horsepower rather than stratospheric peak power and top-speed numbers.

The double-R's twin-spar aluminum frame mirrors the engine's elegantly simple design. Connecting the steering head to the swingarm pivot with an artful combination of castings, forg-ings and extrusions, the alloy-beam frame offers a high level of both rigidity and light weight. The box-section aluminum swingarm is stiffened by a graceful upper brace that takes its final shape as it's extruded, using technology Honda came up with during development of the tour de force Acu-ra NSX automobile.

The CBR measures a positively stubby 55.3 inches between the axles —shorter than anything else in liter-bike land. Factor in a 16-inch front wheel (carrying a 130/70 radial), 24 degrees of rake and just 3.5 inches of trail, and you have a motorcycle that, on paper at least, should flick into corners quicker than you can say "Mick Doohan."

On the road, rest assured it does exactly that. Settle into the firm but reasonably comfortable racetrack-refugee saddle and you feel somewhat perched atop the bike rather than in it, thanks in part to the stubby chassis. The instrument cluster seems close enough to wear as a belt buckle, and feeling as if they're clamped to either side of the front axle, the clip-ons sit low and wide, offering still more leverage to speed after that first quick flick of the morning.

Our test bike started easily, though it proved a bit cold-blooded, demanding a fair amount of choke and throttle fiddling even on warm June mornings. But once the coolant-temperature-gauge needle lifts from its stop, carburetion is exemplary from idle all the way to 12 grand, when the rev limiter ends the party. Full-throttle shenanigans through the first three gears can have the front wheel hovering clear of the pavement, and first-time RR pilots soon learn that safe progress and long life on this particular weapon require equal parts of skill and right-wrist respect.

And though it's hopelessly overquali-fied as a grocery getter, the light, agile RR performs dutifully during weekend errands or on weekday commutes. It's certainly no Gold Wing in terms of plushness, though it works surprisingly well on shorter-distance hops, better than more cramped racer replicas such as Suzuki's GSXRs. Despite this year's gearbox changes, the only real glitch is a somewhat notchy transmission that plays hide-and-seek with neutral and requires a deliberate, precise effort to grab the next desired gear.

The CBR is happy enough during the odd freeway drone, but you'll be happier if the off-ramp du jour is less than two hours away and offers a quick segue to some tasty back roads. Legroom is abundant enough even for long-legged riders, though trips that clock in on the far side of 120 minutes can become a bit painful. And even though the RR's saddle appears to be hard and uncomfortable, its soft foam and nicely contoured shape is surprisingly plush.

The downside? Firm spring and damping rates fore and aft were apparently designed in a world full of highspeed cornering loads but completely devoid of the bumps, holes, expansion joints or pavement imperfections that infect most of the roads we ride. Still, the seriously determined or those with abnormally high pain thresholds—can soldier through the 215 to 220 miles a careful right wrist can squeeze from the 4.75-gallon fuel tank.

There's enough high-frequency buzz sneaking out of the engine bay to turn images in the well-placed rearview mirrors fuzzy beyond 4500 rpm. Unfortunately, that works out to 67.5 mph in top gear with the 900's relatively short overall gearing—right where we spent most of our freeway time. And then there's that svelte fairing and abbreviated windscreen that do a better job of sneaking through the air at high speeds rather than protecting the rider from same. But hey, if you wanted a Stratolounger, you'd have stayed in the living room.

Like most hard-core sport bikes, the RR comes into its own on convoluted bits of secluded back road. On both fast routes and those littered with corners, the RR, with its light weight, quick steering manners, short wheelbase and no-flex chassis, seems to grant a rider's every wish. Midcorner line changes are just a simple push of the clip-on away. Feel like wheelying out of a corner? With this bike's power-to-weight ratio, it's no problem. This is not only the most flick-able open-classer available, but one of the most tossable sport bikes in all of motorcycling regardless of displacement.

All is not perfect in double-R land, however. Firm springs at both ends and a bit of compression harshness up front conspire to deliver a somewhat severe ride on rougher roads. Our '94 test unit does feel more composed than the '93 model we tested (which we later discovered had been hampered by mismatched fork-oil levels), though the RR still won't carve serenely through bumpy corners. This nervousness eventually finds its way to the rider, which takes away some of the rock-steady, confidence-inspiring feel the bike exhibits on smoother stretches of asphalt.

The problem can't be dialed away completely, though the reasonable range of adjustment built into the CBR's suspenders allows riders to soften the bike's legs enough to deal with harsher pavement with one of the softer preload and compression settings. In back, preload settings of two and three (of seven) and minimum compression settings offered the most rear-end compliance on bumpier routes. Softer settings also helped up front, though the downside is excessive fork dive and a bit of bottoming during major-league braking maneuvers.

Control is no problem when it comes to stopping, however. Quad-pot Nissin calipers grabbing 296mm rotors generate linear, wonderfully controllable stops from any speed the engine can generate. Braking feel is excellent, and fade is nonexistent at street speeds. We were equally impressed with rear-brake feel; the rear brake provided good power over a broad band of pedal travel with no tendency toward premature lockup. The sticky standard Bridgestone Battlax radials were excellent as well. The only caveat is that they stick better than they wear; hard riding means you'll be investing in another pair soon.

On the track or on the street, the 900 makes solid, usable power from 4000 rpm on up. Things begin to get serious at 6500, and just before the tach needle hits nine grand, the front end gets light, parting company with the pavement in the first three gears as peak power hits just past 10,000 rpm. The quarter-mile is dispatched in ijust 10.55 seconds at 130.3 mph; ^that's better than every current liter bike save the omnipotent ZX-11.

Maintaining the CBR proves relatively simple. There's an easy-access, spin-on filter for speedy oil changes, and though there's no oil sight window, the dipstick is easy to reach. You've got to remove the cams to replace valve shims, though at least the valve-adjustment interval is a healthy 16,000 miles. Control feel, fit and finish and details such as fastener quality are of typically high quality.

In the end, the beauty of the double-R lies in the laser-light purity of its purpose. Purged of the mechanical split personality afflicting motorcycles that try to be too many things to too many motorcyclists, the CBR900RR is free to be the most serious mass-produced sport bike currently available. Its suspension isn't perfect, though in a world where other supposedly serious sport bikes are gaining weight and losing focus, the RR reminds us that Honda's refined, low-mass approach creates the best big-bore sport bike $8599 can buy. M

Source MOTORCYCLIST 1993