Suzuki’s six-cylinder Tokyo show bike may be closer to production than you think.
From the January 2006 issue of Cycle World
The Stratosphere–it names this new Suzuki six-cylinder show bike, and it also describes the “high frontier”–that strange, elevated part of the atmosphere beyond all weather, where ramjets can breathe.
There are two contrasting ways to look at this motorcycle. The first is to see a quite conventional 3/4-naked sportbike with a unit fairing/tank/seat unit of Craig Vetter/Hans Muth Katana influences, bolted into position on top of it. The Katana is, after all, celebrating its 25th anniversary. Is it a gleaming metallic horse whose legs have become whirling wheels?
The other is to seriously consider the features list and realize that all that you see here can be implemented now. The Stratosphere may in fact be a warning, a teaser for what Suzuki is about to do next.
Start with the obvious–the transverse inline six-cylinder engine, which Suzuki says is no wider than current four-cylinder powerplants. Do the numbers: With 1100cc displacement and current bore/stroke ratio, this engine will be roughly 18 inches wide. Across-the-fairing widths of current 1000cc sportbikes are in the 20-21-inch range, proving the above statement. Even Ducatis have been 19 inches–still wider than our notional straight-Six. And if Suzuki chose a bore/stroke ratio from the previous era, the engine could be as narrow as 16 inches.
Why a Six? The history of the auto industry answers that one–Sixes replaced Fours as soon as price permitted, because they are so much more civilized and easy to live with. They are smooth in every way, being self-balancing for primary and secondary shaking forces, and having 50 percent more propulsive smoothness than a Four (lack of vibration from power-pulsing). Inline-Fours with fair-sized pistons need balance shafts to suppress the buzz of their secondary vibes. Why shouldn’t motorcycles–which need the extra chassis rigidity associated with solid-mounted engines–be as smooth as automobiles? Four-cylinder engines in today’s cars are anything but rigid-mounted–they are elaborately isolated from their chassis by extensive math modeling, testing and plenty of compliant rubber. No such worries with the Stratosphere.
What about torsional (twisting) vibration? The longer a crankshaft is made, the more subject it becomes to such modes, caused by the succession of impulses from the firings of the cylinders. In auto engines, this vibration is suppressed by a dissipative rubber damper on the front of the crank. In motorcycles, the simpler solution is to take power not from one end of the crank but from its center. This cuts the vibrating length of the crank in half, making it effectively stiffer and thereby raising its natural torsional frequencies out of range of excitation by cylinder firings. Engine accessories are located where they belong: behind the cylinders.
How much power? Using 10-year-old technology, 180 horsepower, but pushing as hard as present-day sportbike engine designs do would yield close to 200. In either case, plenty, and with luxurious smoothness. Sixes have a unique exhaust note, too–music.
All that power is delivered to a dual-mode transmission. If you like automatic shifting–or if you are just momentarily tired of rowing the gearbox–this bike will do it for you. But if you require the classic experience, clutch lever and shift lever are there for you. It’s hard to say what’s next, but the work Suzuki undertook toward clutch/throttle/gearchange automation in MotoGP will not just be filed and forgotten. In the 1970s, my own stiff-necked devotion to manual shifting was charmed out of me by 300,000 miles in an automatic van. It could happen to anyone. It happened in Formula One.
I really like the extended tan leather upholstery of the Stratosphere’s seat/tank, as it has long seemed to me reasonable to make the parts of the machine that touch the rider as organic and comfortable as possible.
Now consider the instrument screen, described as a “Multi-Information Display,” or “Full-color LCD screen, more like a television than a normal dash.” Liquid-crystal displays are not new, but aviation is the conceptual leader here. Commercial aircraft no longer have panels jammed with 200 or so individual instruments, but instead feature a “glass cockpit.” This is a large central display screen on which images of the instruments essential for the current phase of flight appear–with emergencies getting priority presentation. With the computing power now available, nothing else makes sense. I like it–except that when the screen goes blank, you lose everything! Even that has already been attended to by aviation: You just triplex or quadruplex the electronics so it takes two or more simultaneous failures to bring the system down. This is already standard with some ABS systems, and not as hard as it sounds because electronics have become so tiny.
Into the Stratosphere went many fine details: Suzuki’s Tokyo Show concept bike points to the future with its color LCD “glass cockpit” and switchable auto- or manual-shift transmission
The tank top features are Select, Menu and arrow buttons to control the display. Hmm, such a display could present anything–GPS and route data are a shoo-in. How about pages from the service manual, on demand? This is fun. Let’s imagine ourselves to Futureworld and hit “Mode”–ah, here’s the expected Cruise, Sport and Ultra-Sport suspension. Wait, BMW already does this with its Electronic Suspension Adjustment on the new K1200S and R! Or how about a rain program for engine power and traction control? But what’s this Autopilot? Click-click to Rossi-mode, sit back and enjoy…
Why no fairing? Because if you have six cylinders, the world wants to see them. The array of chromed headers is positively CBX! They disappear into a blacked-out (which means they don’t want you to notice it) muffler under the gearbox, from which projects a short, three-sided outlet, located on the right. This stubby outlet is in step with the current trend to greatly reduce a traditional long exhaust system’s contribution to the machine’s polar moment, or rotational inertia.
The rest of the Stratosphere is up-to-date but basically conventional, and I applaud this. Revolutions that attempt to change too many things at once usually give insufficient attention to any one thing–and so they fail.
The array of four headlight elements resides in a Ducati 999-like projection booth (or Death Ray?) set into a cleft in the front of the fairing/tank unit, ahead of the steering head. There are historic precedents for surrounding the steering head in this way: Moto Guzzi did it on its early-1950s roadracers, and the French 1957 Derny Taon is gleamingly similar.
Taillights are under a transparent panel that completes the aft shape of the seatback. Brake discs resemble circles of bright cutlasses–a variant of the current “wave rotor” concept that improves braking by providing slots or grooves to clear brake dust from between disc and pad.
Because it’s so boring just to flat-black all plumbing, the Stratosphere’s radiator side covers are given an arty “Damascus steel” look. The fascinating patterns in such steel resulted from repeated cycles of folding and forging. While I agree that its visual complexity beats flat black, do remember not to fire modern loads through Damascus shotgun barrels. They notoriously blow apart.
Suspension is conventional, with an adjustable inverted fork up front and a swoopy-styled, top-braced swingarm at the rear. No revolutions here–just proven technologies.
Surely inspired by the tiny “flyscreens” seen on classic unfaired Manx racers is the adjustable-height, diamond-shaped screen on the Stratosphere. Notice also that one of the Stratosphere photo illustrations shows ghostly bags projecting from the back of the machine. Why not? An inline- Six would be as smooth as a Gold Wing’s flat-Six any day. A motorcycle’s “purpose” is whatever you use it for. Why couldn’t there be a very powerful, super-sporting motorcycle that is smooth enough for touring? That’s civilization.
Will the Stratosphere descend from the lofty world of the show circuit and land on the roads of America? Suzuki wasn’t saying, but did supply video of the bike running at its Ryuyo test track in Japan. Here’s to a successful descent.
Source: Cycleworld
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