Modified 2007 Yamaha YZF-...
Modified 2007 Yamaha YZF-R6S
2007 Yamaha YZF-R6S
To extract the top-end power we knew the R6S would need to compete with the new R6's screaming mill, we turned to Graves Motorsports, perhaps the most experienced shop when it comes to modifying the Yamahas. The company's full titanium exhaust ($1299.99) is a work of art, weighing in at 8.5 pounds-just over half the stock pipe's weight-and installing perfectly. Graves also provided a pre-mapped Power Commander ($339.99) to work with the exhaust system, another easy installation.
Every bit of horsepower and weight is important where middleweights are concerned, and to that end we tossed the stock 532-sized chain and sprockets in favor of a 520 RK Gold RX-Ring chain and matching Vortex sprockets. The narrower chain ($110.50) alone saves weight, but the Vortex steel front sprocket ($30.95) has lightening holes and the rear ($70.95) is CNC-machined 7075 aluminum as opposed to steel. The combination dropped more than 2.5 pounds from the R6, a huge savings.
We cleaned up the Yamaha's rear end with a Competition Werkes fender eliminator kit ($139.95), which includes smaller-than-stock signals and a stainless-steel license-plate bracket. The high-mount Graves pipe just touched the stock turn signal, but there's lots of clearance to the smaller one. Anodized swingarm spools ($29.95) and an aluminum oil cap ($24.95) from Ride Engineering add some bling to the bike.
2001 Suzuki GSX-R1000
Six years and three generations after its introduction, the original GSX-R1000 is still a missile. And we couldn't have asked for a better example than this one we found that belonged to an employee at Suzuki's Brea, Calif-ornia, headquarters. With 25,000 miles on the clock, the bike was in mint shape; the only modification was a Yoshimura bolt-on exhaust, and the GSX-R pounded out 140 horsepower on the dyno-just three less than our own test bike posted in '01.
The original 1000s have torque curves that are flat as pancakes, and, wanting to preserve that as much as possible, we kept engine modifications to a minimum. The exhaust was swapped for an M4 system with stainless steel headpipes, a titanium midpipe and a carbon canister. While the canister is beautifully finished and the individual pieces fit together fine, the M4 needed some coercion and the liberal use of a prybar to have the "two" sections of the header clear the sump on both sides. That sorted, the rest of the system lined up fine. The $987 M4's stainless header scaled in at approximately 1 pound heavier than the stock titanium piece, but that is more than offset by the lighter-than-stock midpipe (we removed the SET valve completely) and canister.
Inside the engine, we installed an STM slipper clutch left over from a previous project. Using a split inner hub with a ball-and-ramp setup, the STM employs a small diaphragm spring to vary the amount of slip and a large diaphragm spring in lieu of the stock coil springs. The clutch installed easily enough, but it's worth noting that the STM's design requires you to remove the hub nut to swap out the clutch plates, turning what is usually a several-minute job into more of a chore. As a precaution, we fitted new steel and fiber plates, and refilled the crankcase with three liters of Maxima Maxum4 synthetic blend oil ($8.67/liter) and replaced the air and oil filters with K&N parts.
 The GSX-R's stock steering...  The GSX-R's stock steering damper had a huge dead spot, so we ditched it and bolted on this Hyperpr RSC active damper kit. | 
|  This STM slipper clutch's...  This STM slipper clutch's diaphragm spring requires a bit more lever effort than the stock coil-spring setup. The clutch slips just enough to reduce chatter on corner entries, keeping the chassis under control. |
It wouldn't do to upgrade the performance of the big Suzuki without bringing the style up to date also. Targa Accessories sent over an impressively well-made rear hugger fender, which bolted up easily with no drilling or modifications. The $199.95 fender adds some bling to the back of the bike, keeps the rear end nice and clean, and matches the rest of the bike nicely. Likewise, Targa's tank cover ($34.50) slipped on perfectly and prevents the tank from getting dirty and scratched. The company also sent over an equally beautiful undertail kit, which replaces the huge stock fender, brake light and turn signals; that stayed in its box as installation required cutting the bungee hooks from the subframe and slicing the back of the fender off, and we didn't want to make any irreversible mods. We did, however, bolt on the Targa anodized lever set ($25.50) and tank screw set ($9.75) to add some color to the front of the bike.
Finally, we topped everything off with a Zero Gravity Double Bubble windscreen ($84.95) that provides more wind protection and better optical clarity than stock, along with some Galindo F1 grips to replace the well-used stock bits.
Metzeler Sportec M3 and Bridgestone BT-002 RS
To keep the old and new bikes on equal footing, we fit each pair with identical tires-Metzeler's Sportec M3 for the two Yamahas and Bridge-stone's BT-002 RS for the Suzukis. This was the only modification for the new bikes; aside from the tire swap, the '07 R6 and GSX-R remained stock.
We fit the new and old Yamahas...
We fit the new and old Yamahas with Metzeler's Sportec M3 street tires.
Introduced last year as a replacement for the Sportec M-1, the M3 features an updated construction, compound and profile, with the aim of increasing mileage and improving wet and dry grip. Editor Kunitsugu detailed the changes and sampled the tires at their introduction (Late Braking, April '06), and was impressed with the performance of the street-oriented rubber. In brief, the front M3's profile is more rounded compared to the M-1's, while the rear incorporates a changing radius that optimizes its footprint at all angles of lean. The material inside the tire, while still Pentec for the cross-ply belts and steel for the circumferential belts, has been changed to make the carcass more pliable, in turn allowing a stiffer, longer-lasting tread compound.
We fit both Yamahas with 120/70 front and 180/55 rear sizes. Both bikes exhibited light, neutral steering with no instability, and traction was excellent overall. The Sportecs did feel stiffer and slightly less compliant than the Dunlop D208s fitted as standard equipment to the R6S and the Dunlop Qualifiers that were originally on our '07 R6, but wear appears to be better so far. The Sportec M3 is available in a variety of sizes, including the 65-series front that came as standard on the R6 until '05. Visit www.us.metzelermoto.com or call (800) 747-3554 for more information.
Bridgestone's new BT-002 RS (racing street) tire is a street- and track-day-oriented version of the company's BT-002 Pro DOT race tire. The front tire has a medium-compound center section and soft-compound shoulders to provide a balance of grip and mileage, and HTSPC-MSB (high tensile super penetrated cord-mono spiral belt) technology in both front and rear tires increases stability and reduces heat generation. One factor that led to our choice of the BT-002 RS for the two Suzukis is that the tire is offered in the GSX-R1000's OEM 190/50 rear size as well as the more racetrack-oriented 190/55 size. We used the lower-profile 50-series tires, which required no suspension or geometry adjustments to the '07 1000.
The two Suzukis were shod...
The two Suzukis were shod with Bridgestone's BT-002 Racing Street Tires.
The Bridgestones provided excellent traction on both bikes, with outstanding grip at full lean on smooth pavement. One notable characteristic of the tires is their warm-up time, which is significantly quicker than some other street/ track hybrid tires we've sampled. The BT-002 RS is available in 120/70 front and 180/55 rear sizes in addition to the sizes mentioned above. For more information, visit www.motorcycle karttires.com or call (800) 543-7522.
NEW VS. OLD PERFORMANCE NUMBERS
| STOCK 2007 | MODIFIED 2001 | STOCK 2007 | MODIFIED 2007 |
| SUZUKI GSX-R1000 | SUZUKI GSX-R1000 | YAMAHA YZF-R6 | YAMAHA YZF-R6S |
| weight | 471 lbs. | 445 lbs.- | 422 lbs. | 412 lbs. |
| quarter mile | 9.741 sec. @ 149.31 mph | 10.10 sec. @ 141.70 mph* | 10.854 sec. @ 127.44 mph | 10.831 sec. @ 127.5 mph * |
| roll-on, 60-80 mph | 2.90 sec. | 3.26 sec. | 5.08 sec. | 4.89 sec. |
| roll-on, 80-100 mph | 2.99 sec. | 3.24 sec. | 6.31 sec. | 4.40 sec. |
*Our dragstrip session was cancelled due to excessive wind, so we pulled quarter-mile numbers for a stock '01 GSX-R1000 from our June '01 full test and for the stock '07 R6S from the "Get Real!" test in the Oct. '06 issue. Both the modified old bikes are lighter than their stock new counterparts, and the R6S posted better roll-on times than the new bike.