Yoshimura Suzuki Katana 600
YOSHIMURA SUZUKI KATANA600
THE CARBON-FIBER SPECIAL
FEW NAMES IN MOTORSPORTS CONJURE THE sorts of images that Yoshimura does. Best known in the U.S. for its factory-backed Suzuki Superbikes, the Yoshimura team has served as a springboard for roadracing stars Kevin Schwantz and Doug Polen, among others. Naturally, Yoshimura Research and Development of America (4555 Carter Court, Chino, CA 91710; 714/628-4722) has plenty of experience building Suzukis—particularly GSX-R750s, on which the Katana 600’s motor is based.
When we first contacted Yoshimura's Suehiro Watanabe about building our Suzuki, we were worried that he wouldn't w ant to participate. After all, the bike's air-and-oil-cooled engine is an older design, and 600 Katanas have fallen out of favor with roadracers—to the extent that the Katana class was axed from the I 990 Suzuki Cup Finals. How could he hope to compete with the Honda and the Yamaha, and what benefit would he derive?
Well, outdated or not, the Katana 600 has been the best-selling Suzuki streetbike for the past few years— largely due to its low price—which means there's a slew of potential buyers for hot-rod Katana parts. With that in mind, 'Nabe agreed to participate. We're glad he did, because until Suzuki unveils a GSXR600, this bike is as close as anyone is likely to get.
From the carbon-fiber stanchion tubes of its prototype upside-down Kayaba fork to the carbon-fiber silencer clamped to its titanium Duplex 4-into-2-into-1 exhaust system, and with its custom paint scheme, this particular Katana is like none we've seen. It even feels different, with its relatively wide handlebars and radically rearset footpegs giving it a far more sporting bent than the stocker.
It works better than stock, too, with wide Performance Machine wheels—an 18-incher at rear—fitted with Michelin Hi-Sport radiais. Nissin front, and Performance Machine rear brakes, with Russell braidedsteel teflon lines and SBS pads offer improved stopping power. An Öhlins shock and gusseted swingarm provide roadholding that—while no match for the otherworldly fork—is far better than that of showroom Katanas.
As good as the chassis is. it's got nothing on the motor. A Yoshimura induction kit routes air drawn through the stock fairing scoops to the space where the airbo.x used to be. A bank of four 36mm semi-flatslide Mikuni carburetors f rom a 1989 GSX-R I 100 feeds the motor, while, in similar parts-bin fashion, a larger oil cooler from an '87 GSX-R l 100 keeps operating temperatures down, and the stronger transmission from a '90 GSX-R750 puts the power to the driveline. Wiseco pistons, stage 3 camshafts, heavyduty valve springs with titanium top retainers, and a heavy-duty camchain and tensioner complete the parts list. Stage 3 porting, crankshaft balancing and more than eight hours of dyno time round out the labor column.
Most impressive is the Yoshimura Suzuki Katana’s weight savings. The bike is a full 41 pounds lighter than stock.
Total cost of parts and labor, not including the bike's purchase price, the carburetors, oil cooler and transmission—and substituting an aluminum upsidedown fork for the as-vet-unavailable carbon-fiber unit—is just shy of $12,000.
Hard to justify? Maybe. But it's a small price to pay for the world's only GSX-R600. —Brian Catterson
