Get the Flash Player to see this player."These things don't belong on the street!"
This has become the cry of the rational motorcyclist when the subject of modern literbikes comes up. But what if you could have virtually all of the same performance-driven componentry and research and development that go into most superbikes in a motorcycle with roughly 30-35% less spank? Would most riders, young and old, veteran and newbie, feel like they could handle such a bike? Apparently, yes.
Supersports, or more commonly, 600s, are red-hot sellers. Editor Duke reported back from his time at the U.S. launch of the 2008 R6 that the tuning fork company claims "the 600cc segment makes up 51% of what Yamaha calls the Supersport market, a segment that is up in sales a huge 52% since 2001." Yep, these things are pretty important.
Changing of the guard?
As a matter of fact, the supersport class may become even more important to OEMs than it already is –whether they like it or not. When the AMA essentially admitted to its ineptness at handling American pro racing and announced in March of this year that Daytona Motorsports Group was granted rights to promote, sanction and manage various AMA racing series, one of DMG’s first moves was to change the current structure of road racing. Starting in 2009, the premier class will likely be the “Daytona Superbike” class. As of the writing of this story, DMG hasn’t yet released specific rules for the new class but has stated that the collection of contenders will include Twins, Triples and four-cylinder bikes, and will have “middleweight performance horsepower limits,” said to be 140 rear-wheel horsepower. In effect, this opens the door for six more brands that DMG says fit the bill: Aprilia, KTM, Triumph, BMW, Ducati and Buell.
Well then, guess it’s a good thing we got around to testing at least 5 of the 10 bikes potentially eligible for the new Daytona Superbike class.
Like our literbike shootout from last month, this battle supreme has a couple of freshened-up entrants mixed in with a couple of models not yet at the end of their model cycles. AMA Formula Xtreme reigning champ, Honda, is naturally in the fray with its CBR600RR unchanged from last year; same goes for Kawasaki’s 2007-08 Daytona 200-winning ZX-6R.
Though it can’t lay claim to any U.S. championships, the Daytona 675 from Triumph – unrevised since its ’06 intro – is a champion of the hearts of many and has taken top honors in the Supersport class at the Spain-based track-centric Supertest three years running now, and three-peated this year in the same category in a similar uber-evaluation called Masterbike run by the Spanish sportbike mag Motorciclismo. Tooting our own horn a bit while paying further accolades to the English Triple, the 675 won Motorcycle.com’s 2006 Supersport shootout as well as our 2006 Best of the Best comparison. Phew! That’s a tough act to follow.
This leaves the two newest bikes: the Yamaha R6 and Suzuki GSX-R600. Both bikes received a healthy dose of revision but not so much as to make either wildly different from last year.
For ’08 the R6 gained YCC-I (Yamaha Chip Controlled-Intake), first seen on the 2007 R1. Both supersport and liter machines from Yamaha now have throttle-by-wire (YCC-T) and YCC-I. In addition, the middleweight mill received upwards of some 50 tweaks, a couple of them being increased compression and substantially larger crossover pipes in the exhaust headers; the targeted goal being improved mid-range. To augment engine improvements, the R6’s frame was updated to enhance both rigidity and controlled flex in all the right areas. The aluminum subframe was tossed in favor of one constructed from magnesium. Finally, things like altered clip-on placement, new EFI, 0.5mm thicker rotors for improved heat dissipation and revised bodywork join numerous other changes that add up to what Yamaha calls a “brand new bike from the tires up.”
Suzuki has reason to be proud of the GSX-R600. According to Garrett Kai, American Suzuki’s Senior Communications Specialist, it is the best-selling machine of all the products in the company’s catalog. The little Gixxer got a gaggle of improvements this year, and like the R6, a heavy focus was on mid-range power improvements. Compression was pushed from 12.3 to 12.5:1, intake ports were reshaped, valve lift was reduced on the intake cams and exhaust pipe diameter was reduced by a scant 3mm while overall muffler volume increased. Fueling was enhanced and ventilation between cylinders was increased marginally to reduce pumping losses. Though the chassis remains largely unchanged from last year, the GSX-R600 picked up an electronically controlled steering damper. Improvements to braking come via changes to increase pinching power without increasing effort at the lever. Oh, and we almost forgot, to complete the circle, so to speak, the 2008 GSX-R600 now, like all current Zook sport bikes, has the A-B-C of Suzuki–Drive Mode Selector.
Back in the saddle
With the players in place we summoned a motley collection of hapless riders eager for a spin on the latest 600cc hardware and a free meal at Outback Steakhouse. Fresh from our literbike rumpus is ex-Limey, Steve “Speed” Kelly. Steve’s a salty veteran of the motorbike courier world, first in Ol’ Blighty, then sunny L.A. He’s owned more bikes – and sold ‘em at a profit! – than George Barber, holds a WSMC racing license (sourced from an I-5 rest-area bathroom) and has countless miles round a track. He’s plenty qualified, but we just like his accent.
Also returning – and still suffering mental duress – from the literbike battle is Alexandra Bongart. Alex owns a late-model GSX-R600, knows her way around the pits and track, and is an accomplished street rider. She brings a fresh, female perspective to Motorcycle.com, which is very important these days and rarely, if ever, seen in most publications. I hate to admit it, but I’ve had a hard time keeping her out of my mirrors during street rides.
'...we logged hundreds of street miles through twisted mountain pavement, urban sprawl and droned the superslab'
New to the tomfoolery is Kaming Ko. This incredibly friendly character has a lengthy resume in Formula car racing a well as a ‘70s motorcycle racing survivor. Kaming’s riding style is a dead give-away to his age, as some fused vertebrae keeps him from laying over the tank in a sportbike tuck, but he still rides faster than most us who have a fully functional spine! Again, like the other two above, we really keep him in the mix for ulterior motives. He has owned some of the coolest sportbikes ever built, like the Desmosedici RR he recently let Editor-in-Cheese Duke and me bumble around Willow on.
Finally, this time we added someone as sharp with a keyboard as he is with a twist-grip. Mark Gardiner is to motojournalism like a wrongly-accused inmate is to death row: full of time served and glad to be out. Jesting aside, it needs to be known that Mark worked at Motorcyclist magazine for a stint, raced in the Isle of Man TT, and is an accomplished author with his well-received book, Riding Man, about his TT experience.
Over the course of several days we logged hundreds of street miles through twisted mountain pavement, urban sprawl and droned the superslab. Mix in one nearly perfect day on the Big Track at Willow Springs Raceway in Rosamond, CA, where we doubled-up on sessions courtesy of trackday company, Take It 2 The Track, and we were ready to cast ballots in hopes of a clear-cut winner. Clear-cut? Pfft!
We employed the same scoring method as in this year’s liter comparo wherein we took a cumulative sum of scores over 12 categories – with the same bias toward the Engine category – that encompass the things we care about in a motorcycle.
(power, tractability, response, user-friendliness, vibration)
Surprise! Not exactly, but the Honda’s powerplant, being as linear as it is, can’t quite compare to the 675’s, according to the unblinking Dynojet at our friends at Area P. In classic inline-Triple fashion, the Daytona makes the best use of its shootout-leading 47.9 ft-lbs of torque in a very manageable way starting from as early as 3,000 rpm where it’s making 36 ft-lbs. At that same mark the CBR, the next most potent powerplant, is only making 21 ft-lbs. This middleweight represents with near perfection the characteristics we look to consider when assessing the engines. Power comes on early and isn’t absent in lower rpms like so many flaccid 600cc mills. The smooth on/off throttle transitions of the 675 translates into the most tractable bike here. Driving into and through Turn 8 at Willow revealed a rheostat-like quality: dial the power in, roll it off gently, and then turn it back up. On the street, Mark and Kevin kept using the phrase “cheater motor” after climbing out of the saddle with silly grins on their faces.
Set the oddball aside for a moment and the CBR is clearly the best powered of the four Fours. In many ways it mirrors the 675. It, too, has an exceptional amount of user-friendliness, as it doesn’t require its neck be wrung for maximum fun. Feed the throttle in from way down the rpm range and the Honda pulls more like a 750cc Four, its powerful grunt belying its displacement. “Not sure how the hell Honda does it, but this bike rips out of corners,” exclaimed Speed Kelly. That’s a good observation considering it shares identical bore and stroke figures (67 x 45.2mm) with the other three Japanese machines. The simple answer is that the CBR is just a tick shy of the 675 in terms of horsepower and torque. With 105 ponies peaking at 14,100 rpm and 46 ft-lbs maxing out in the 12,500 rpm neighborhood, it’s a force to be reckoned with and understandable why the bike has been so successful in AMA Formula Xtreme.
It seems Suzuki’s efforts paid dividends in the search for more mid-range usability. It doesn’t have the stonk of the 675 but pulls with authority – save for a soft spot around 7,000 – as early as 4,500 rpm making 30 ft-lbs. The GSX-R600 actually outpaces the CBR’s torque figures by 2-3 lbs on average from just below 3k until about 8k where the CBR leaves the Gixxer behind. The strange thing here is that seat-of-the-pants sensation is quite the opposite. We’re attributing the Honda’s shorter gearing for its extra-torquey feel. The Gixxer offers smooth throttle transitions and trouble-free fueling that are the work of Suzuki Dual Throttle Valve system, and a new ECU controls fueling as well as a valve in the exhaust system. Torque is quickly becoming the new catch-phrase in supersport tuning. The end result is a more robust spread of power that brings the GSX-R closer to the CBR and Daytona in terms of greater everyday usability. One small negative with the Zook’s mill is that seemed to be buzzier than most on the freeway.
The current ZX-6R is likely at the end of its lifecycle, and it’s starting to show in the face of the competition. Before all the Ninja loyalists start planning to burn us at the stake for such blasphemy, we fully and readily acknowledge the ZX as a very excellent choice, and the Ninja’s motor seemed the smoothest among the buzzy inline-Fours. But, the Green Machine was dead last in the horsepower race, posting a sub-par 97.7 hp in stock form, according to our pals at AreaP and their reliable Dynojet dynamometer. There’s something of a minor controversy regarding the tuning of the ZX, something you’ll want to read more about in the below sidebar.
ZX-6R Free Horsepower!
Pity the poor sportbike engineers who must find a way to create 599cc engines that produce 100 horsepower at the rear wheel while meeting every-stricter exhaust emissions regulations. And while spent exhaust gases must be cleaner than ever, noise emissions must also be kept in check, although that standard hasn’t been revised in decades.
Nowhere is that more apparent than Kawasaki’s ZX-6R. Since its 2005 iteration, the ZX’s ECU includes programming which closes a valve in the exhaust at high revs, restricting its top-end power and reducing its overrev zone past the engine’s power peak. (European ZX’s aren’t afflicted, as they have different sound-level regulations across the Pond.) This combines to make the stock Ninja feel less exciting, and its rapid power loss once past the engine’s peak forces some extra gearshifts, especially when riding in the power-hungry environment of a racetrack. Our ZX test unit was the least powerful 600 on the dyno, spinning up just 97.7 hp at its peak.
But why is the Kawi saddled with this limitation while the other OEMs don’t seem to suffer from similar programming? That’s been difficult to identify, but Kawi reps assure us their bikes adhere to the obfuscatory EPA noise regulations guidelines that are self-regulated by the OEMs.
“All Kawasaki street motorcycles, including the Kawasaki Ninja ZX-6R, sold in the United States have been designed to meet all current U.S. emissions and noise regulations for street-legal motorcycles,” is Team Green’s official statement on the subject. Since the sportbikes from other OEMs aren’t similarly affected, the implication is they aren’t meeting the same requirements.
Glenn Hansen, Suzuki’s communications manager, explained to us that the ECUs on Suzuki products bound for America are different than their Euro counterparts, and he added that all their bikes meet current regulations. He pointed out that using dual mufflers on Suzuki’s GSX-R1000 was partially the result of meeting noise edicts.
Lucky for ZX trackday riders (off-road-use only, doncha know? Nudge, nudge, wink, wink, say no more…), the party-pooping programming can quickly be defeated. Simply unplug the cap of the four-pin electrical connection under the seat and bridge the black/yellow wires to the green/dark green wires across from each other in the connector. This defaults the ECU to European spec and lets the engine breathe at high rpm by keeping the exhaust “power” valve open.
When we performed this trick on our ZX, we found a 5-hp increase (102.8 hp) in peak power, making it competitive with its rivals, but the biggest improvement was in the overrev zone above 13,000 rpm where the stock ECU programming strangles the Ninja. There is nearly a 10-hp gap at 14,000 rpm, with the stock bike wheezing out 93.4 ponies to the modified ECU’s 102.7.
It should be noted that the Ninja doesn’t feel particularly down on power during street rides, as it’s only when screaming up near maximum revs that this shortcoming becomes apparent. But it’s too bad that the stock bike needs an excuse, because in race trim the ZX-6Rs are formidable foes in the Supersport and Formula Xtreme race classes.
The R6 trails behind the others in terms of streetable power. It doesn’t make 30 ft-lbs until 6,000 rpm, then manages to dip below 30 for a short rpm range, then regains its composure at almost 8,000 where it barely makes 31.5 ft-lbs; at 8k rpm the Gixxer is making nearly 6 more ft-lbs. Though the ZX-6R sees a modestly better 32.5 ft-lbs in the same spot, it’s more linear much earlier than the R6 as it starts to see those 32 ft-lbs as soon as 5,000 rpm. Where the Yamaha shines is beyond the 13,000 mark where it screams, quite literally, to 100 hp, leaving the green bike in its dust. Unfortunately for street riders, the fun zone on the Yammie is all at the top. Racers won’t care.
(clutch actuation/modulation, shift ease, precision, slipper clutch)
The two-year old Ninja may be lagging a bit these days in overall peak power and torque figures, but it seems it is still a step ahead in the gearbox game. The close-ratio six-speed cassette-style tranny is the poster kid for snick-snick shifting. Not unlike its bigger brother, the ZX-10R that shared top honors in this category with the Honda CBR1000RR in our liter comparo, the 6R’s tranny is essentially transparent. Taskmaster Duke often spoke of the 6R’s shifting as “light-action,” and never seemed anything short of impressed with its slipper-clutch. For myself, I couldn’t deny the impeccable function of the components that make the bike shift, but I also couldn’t help but note – whether on track or street – what felt like short gearing on top.
There’s a pretty big gap between the Kaw and the Suzuki here, but the Zook is still pretty damn good, especially its back-torque-limiting clutch. As Kevin reported from his time at the Misano unveiling of the ‘08 Suzuki, the company “… added an additional clutch plate with revised friction material and a modified drive cam shape.” Those minor clutch tweaks and a very smooth shifting transmission kept the junior Gixxer solidly in second in this category.
“Why such a poor showing for the CBR,” you might rightly ask when normally it’s raves all ‘round for most Honda shifting. The fact is that the RR is really quite good – as basically all of them are – but in such a closely contested battle small things stand out. There are some commonalities and some stark differences in this quintet: all five have cable-actuated clutches, yet only three have slipper clutches. The Honda is one of two slackers. Now that Big Red’s liter machine has one, Honda’s fans can sleep easy tonight knowing that the next iteration of the CBR600RR will have one too.
The R6’s biggest failing was a clutch that engaged near the end of lever travel making for some temperamental shifting on the street and thus was relegated to fourth spot. The 675 suffered “slightly notchy” shifting and is the other delinquent in this group without a slipper
(quickness, feedback, stability, confidence)
Claiming its first, first-place finish in the category of Handling, the nimble CBR600RR did the best job in the majority of our testers’ minds. Its chassis dimensions aren’t exceptionally flightier than the other four, and it is only rivaled by the 675 which has substantially shorter trail (86.8 vs. 97.7mm) and identical rake (23.5º). Nevertheless, the Honda simply was “the easiest to flick from side to side, yet was super stable mid-corner,” according to trackday junkie Steve. Along with the shortest wheelbase (53.9”) the Honda boasts the most advanced steering stabilizer in the group. Having improved greatly from its first edition, the HESD – discreetly hidden under the front lip of the fuel tank – is the perfect ally to “add stability to a bike with aggressive steering geometry,” notes Duke. If there’s a drawback to the HESD it is that steering can seem a touch on the heavy side when initiating a turn at high speeds, as the complex steering damper considers vehicle speed, throttle position and rate of acceleration when determining the amount of resistance to apply. The CBR’s handling is also aided by the superb Dunlop Qualifiers.
The Daytona most closely resembles the Honda’s handling as it has the aforementioned tiniest trail figure that could make for skittish handling, but it’s balanced out by a 54.8-inch wheelbase and a non-electronic steering damper. In addition, the 675 is the most waif-like in the collection. From tip to tail the Daytona is skinny. The bike’s narrow waist and slim fuel tank make for easy and unencumbered movement across the saddle when transitioning between corners. Add in the most excellent Pirelli Dragon Supercorsas, and it starts to become clear why the Tri has been the top choice in so many magazine evals and large group tests.
The Ninja still managed to “feel lighter than the 675” at the track according to El Duke, despite the longest wheelbase at 55.3 inches, a modest 25 degrees of rake and a crazy-long-by-class-standards 109mm of trail. The 6R’s wide, flat clip-on placement helps mask the lazy geometry, as does its lack of steering damper. Its stability-inducing geometry and a set of Bridgestone BT015 tires had Speed Kelly saying the “Kawi handled like it's super-glued to the tarmac!”