It can be pretty tough keeping up with the Joneses these days. Especially with the cutthroat state of competition among manufacturers ramping up development cycles to unbelievably rapid levels. You proudly ride out of the dealership on the latest and greatest after selling your favorite steed and pinching pennies, only to see photos of next year's faster and better model already appearing in magazines. It can be depressing to some; almost as if the performance life span of a sportbike can be measured in months, rather than years.
But is it really that bad? Do you think that just because your neighbor recently took delivery of the latest 2003 model, your slightly older model is a pile of junk? What if you installed some choice performance modifications to your older-generation model to try and bring it up to par?
The staff here at Sport Rider decided to see for ourselves how this concept would play out. We took a pair of older models (a '98 Yamaha YZF-R1 and an '02-which is basically identical to the '00 model-Kawasaki ZX-6R), fitted them with suspension and mild engine modifications within a practical budget and pitted them against their latest-generation brethren (an '03 R1 and ZX-6R) on the racetrack to see if the performance bar could be equaled-and perhaps to see just how far the new models have come.
PROGRESSION OVER THE YEARS
The previous version of Kawasaki's ZX-6R actually dates back to '95, when the company introduced the first-generation 6R to replace the overweight, somewhat soft-focus ZX-6E. A far sharper, shorter, smaller middleweight, the 6R put Kawasaki back in the 600-class hunt. It boasted all the usual improvements aimed at better performance: a twin-spar aluminum frame, a highly-oversquare bore/stroke configuration motor and a more aggressive riding position. The same basic design then underwent two more upgrades in '98 and '00, with each generation getting additional engine and chassis updates aimed at keeping pace with the increasingly capable competition.
There were some significant changes to the '98 and '00 versions. (Rumor has it that Kawasaki basically had all three versions mapped out from the start, and simply upgraded to the next level when engineers deemed it necessary.) The first revamp in '98 saw various minor engine alterations cut four and a half pounds of excess heft, but the big mods were reserved for the chassis. A 13mm shorter wheelbase (to 55.07 inches), steeper rake (from 24 to 23.5 degrees) and shorter trail (85mm) tightened things up in the steering department. The 6R also received beefier 46mm tubes in its conventional cartridge front fork, and six-piston calipers for increased braking power. The rear rim was also enlarged one half inch to 5.5 inches in width to accommodate the new 180-size rubber that was starting to appear on middleweight sportbikes.
When the Y2K ZX-6R made its debut, it was the engine's turn to get spruced up. The cylinder head received a semi-hemispherical combustion chamber that boosted the compression ratio to a stratospheric 12.8:1, while the carb manifolds were shortened 7mm. Redesigned pistons were mated to an electroplated, aluminum closed-deck cylinder assembly, and stronger rods were connected to a 12.3 percent lighter crankshaft, along with a seven percent lighter flywheel for quicker acceleration. Other changes and improvements cut another 7.7 pounds compared to the previous 6R engine. Further revisions to the chassis (including a decrease in triple-clamp offset for 2mm more trail) and suspension (stiffer spring and damping rates) were also made. By the time Kawasaki was done, it had a 435-pound 600 cranking out 95 horsepower-quite competitive for its time.
Time waits for no sportbike, however, and it didn't take long for the competition to leave the ZX-6R looking a little gray around the edges two years later. So when Kawasaki struck back with the latest-generation ZX-6R, it didn't pull any punches (including boosting displacement to 636cc). It's pretty hard to argue with a package that pumps out an astounding 107.5 horsepower while only weighing 417 pounds wet. Could we make the older-generation 6R even come close to those performance specs?
Although the '03 Yamaha R1's 43mm inverted fork performs well, we actually preferred the Race Tech-modified 41mm fork on the '98 model, which provided more consistent damping and chassis control. We felt the same regarding the stock '03 Kawasaki ZX-6R fork; the 46mm conventional fork on the older 6R modified by Traxxion Dynamics simply worked better.
We were thinking it might be even tougher with the Yamaha YZF-R1. Not since Honda's CBR900RR has a motorcycle made such an impact on the sportbike world. Noticeably sharper-edged than the competition and taking power-to-weight ratios to a new level, the R1 simply trounced everything when it debuted in '98. The 998cc four-cylinder pumped out gobs of power (our test unit rang up 127.8 horsepower) and torque seemingly right off idle on up to its screaming 11,750 rpm redline. But the R1 also had the legs to go with that speed. The aluminum twin-spar Deltabox frame saw several innovative principles that have since become de rigueur in sportbike design, including a long swingarm for improved rear-tire traction. Other features, like the "monoblock" four-piston front-brake calipers, set new standards for performance, and the R1's styling has influenced countless designs since then.
Despite ruling the sportbike world for two years, Yamaha didn't rest on its laurels, giving the R1 a plethora of minor updates in '00 to keep that edge sharp enough to ward off the competition. Refinement was the name of the game, with subtle alterations to the engine, chassis and ergos aimed at allowing riders to extract the most from the package. All those minor tweaks (over 150 in all) paid off in the end-the '00 R1 garnered SR's Bike of the Year trophy due to its polished, well-defined performance.
But even bigger changes were in store for '02. Most notable was the long-overdue switch to fuel injection. But just as the carbureted R1 set the standard for smooth, yet crisp throttle response, the fuel-injected R1 continued that reputation with its innovative vacuum-slide design offering the best overall manners of any EFI-equipped four-cylinder to date. Substantial updates to the chassis (including a revised frame/swingarm, and an engine relocated for centralized mass) and suspension (stiffer spring/damping rates, larger fork tubes) completed a stunningly capable package that stomped out 136 horsepower while weighing only 438 pounds.
BEEFING UP THE OLDER GENERATION
The biggest deficit facing the older Kawasaki would have to be engine power. It's kinda tough being compared to an engine that not only has the benefit of several years of R&D, but also sports 37cc of added displacement. Check the sidebars for details, but we basically fitted some aftermarket products that any person would buy: an Akrapovic exhaust, a jet kit from Ivan's Performance Products and a Factory Pro Tuning Components ignition advancer (+4 degrees). Lo and behold, the combination of parts woke up the old ZX-6R like a triple espresso, to the tune of 104 horsepower! An almost 10 percent jump in power from just those modifications was pretty impressive, proving that stock exhausts from that period can still be improved upon.
We had previously fitted our '98 R1 with a Scott's Performance steering damper. This rotary-style damper is one of the best units on the market today, with high-quality construction, superior adjustability, nonintrusive mounting (no drilling required), and a less crash-susceptive location.
Updating the suspension looked to be a slightly less daunting task, especially with the older 6R's stout 46mm conventional cartridge fork. Traxxion Dynamics fiddled with the stock internals on the fork, but Marc Cook (owner of this ZX-6R) decided that serious performance and multiple adjustability was vital for this semi-track-day machine's rear suspension, so he splurged on a Traxxion-tuned Penske unit. It wouldn't be possible to update the brakes to performance approaching the new 6R's radial-mount/four-pad calipers without spending wads of cash, so we opted to replace the stock brake pads with DP's RDP racing items; Spiegler braided-steel brake lines firmed up the brake-lever feel.
Although we didn't get a chance to try an ignition advancer on the older R1, we weren't really sure it was necessary. Simply adding a Yoshimura exhaust and Factory Pro Tuning Components jet kit bumped up power to an unbelievable 141 horsepower-more than 13 ponies stronger than the stock '98 model's 127-horsepower output. For upgrading the suspension components, we turned to Race Tech, who revamped the suspension rates and installed its famous Gold Valves in the fork and shock. DP's RDP racing brake pads replaced the stock units (check sidebar for details).
In order to keep the traction equation even and up to high-performance specs, we fitted both the Kawasaki ZX-6Rs with Pirelli's Dragon EVO Supercorsa in super-soft front and soft rear compounds. The Yamaha R1s received the same equalization treatment, getting fitted up with Dunlop's latest D208GP "A" DOT racing rubber.
TAKING UP THE CUDGELS
We conducted our track testing at the Streets of Willow's tight and twisty 1.9 miles of pavement. In order to even up the score traction-wise, Pirelli's superb Dragon EVO Supercorsa DOT racing tires were fitted to the 600s, while Dunlop's omnipotent D208GP "A" DOT racing buns were mounted on the R1s.
One aspect was immediately apparent when jumping between the two ZX-6Rs: The ergos on the older-generation Kawasaki felt like a sport-touring bike compared to the '03 model's short, sparse cockpit. But while the riding position of the newer model felt more natural when winding up the pace, the old 6R worked just as well; it only required a little adaptation when cornering hard. Nonetheless, the old 6R surely is more livable on the street.
Amazingly, there really wasn't that much between the two Kawasakis on top (as exhibited by the dyno charts). Both bikes pulled surprisingly hard for middleweights, making good power up to approximately 13,000 rpm. Powering off the medium-speed corners felt the same for both, and we actually preferred the Traxxion Dynamics suspension on the old Kawasaki to the newfangled stock '03 units. Spring and damping rates were matched much better, and the excessive high-speed compression damping of the old 6R was all but gone; the new 6R, however, still suffered a bit in this area, and got a little nervous when pushed in bumpy corners. And while the newer-generation Kawasaki steered more quickly, the aggressive front-end geometry cried out for a steering damper, something the older model didn't need.
We were also impressed by how well the old six-piston calipers responded to the DP brake pads. While not providing quite the stupendous power and progression of the newer model's fantastic radial-mount/four-pad brakes, the DP-equipped older 6R exhibited excellent power and feel, enabling us to brake much later and carry more corner entrance speed than we ever could with the stock '00-'02 Kawasaki.
In the end, it was very close between the old and new ZX-6Rs, with the '03 Kawasaki posting a 1:28.06 lap time to edge out the older model's 1:28.90. Where the old-generation 6R lost most of its time was in acceleration; the '03's transmission ratios are much closer and shorter, and the new engine revs much quicker. This allows it to jet between corners in less time, despite our older model's shortened final gearing and almost equal horsepower.
It was just as close between the R1s, and the older model actually accelerated more fiercely up top, with a definite horsepower advantage. Had we tested on a faster circuit, we figure the times would have been even closer, as the '98 Yamaha really got into its stride above 8500 rpm. Again, we preferred the Race Tech-modified suspension on the older model to the stock units on the '03 version. Damping and suspension action felt much more consistent, especially in the faster and bumpier sections of the course, where the '03 R1's front end would get just a bit nervous.
Since there wasn't much change between the '98- and '03-model Yamahas in the front-brake department (only a switch in caliper-piston metallurgy for a slight weight loss), the DP brake pads on the older R1 provided a distinct advantage. While outright power was about the same, progressiveness, feel and crispness were much better than the stock units on the new Yamaha (which aren't bad in any sense of the word).
Despite those advantages, however, the new R1 just edged out the older-generation model, clocking a 1:27.21 lap time to the '98 version's 1:27.95 best lap. The tighter sections of the Streets course proved to be the modified Yamaha's undoing. Obtaining that horsepower advantage on top with the '98 model required jettisoning the EXUP valve in the exhaust, and some of the low-end crispness in throttle response was lost with it. The '03's fuel injection was precise at every rpm, enabling it to launch off the slower (and even medium speed) corners before the '98 version could stretch its legs. Our '98 test unit also suffered from a slight clutch-slip problem toward the end of testing.
The newer R1's increased agility also helped it get through the tighter sections more quickly. The steering geometry and engine-placement changes to the new Yamaha enabled it to flick through the Streets' multiple corner combinations with greater ease and precision. While the old R1's steering was by no means truckish, the more agile handling of the new Yamaha definitely paid dividends in corner speed while flicking through the slower stuff.
THEY MAY BE OLD, BUT THEY CAN HOLD THEIR OWN
It's easy to get lost in all the hype surrounding any new model. All the latest flash and technology can wow the crowds at the local sportbike hangout, and while the performance may ultimately be superior, it doesn't mean your favorite mount of several years is now a relic of the past. A few choice modifications can bring the performance of any older machine up to spec; all it takes is the right components, and the riding skill to make use of them.
Ivan's Performance Products recommended the Akrapovic pipe for Cook's 6R, so we obtained one of its Evolution racing units. The exhaust system was easy to install, providing a very impressive power boost while shedding 13.5 pounds of weight from the stock exhaust.
'00-'02 Kawasaki ZX-6R Mods-Surprising Gains
No one could accuse us of being somewhat pessimistic when faced with the task of bringing the previous-generation ZX-6R up to spec power-wise with a newer model boasting nearly 12 horsepower more. Gaining even a five percent boost in power could be considered a major accomplishment with a 600.
Marc Cook (owner of this '02-model 6R) heard good things about the 6R's response to an Akrapovic exhaust from Ivan's Performance Products, so we ordered up an Evolution system from Lockhart Phillips USA ($1395; 800/221-7291; www.lockhartphillipsusa.com), and complemented it with a jet kit from Ivan's Performance Products ($120; 845/362-1212, www.ivansperformanceproducts.com). Interestingly, IPP recommends against an aftermarket air filter, stating that they flow no better than stock. Marc also sourced a Factory Pro Tuning Components +4-degree ignition advancer ($54.95; 800/869-0497; www.factorypro.com).
Since Traxxion Dynamics felt it wasn't cost-effective to bring the stock ZX-6R shock up to aftermarket performance specs, Cook decided to splurge on a fully-adjustable Penske 8981 shock. This high-quality unit is easily one of the best available, and well worth the money.
To say we were surprised at the result would be understating the case slightly. Marc's 6R went from a stock 95 horsepower to an absolutely stunning 104 horsepower at 11,500 rpm-a nine-horsepower increase. That equates to a very impressive 10 percent boost in power on a 600 from just a pipe, jet kit and ignition advancer. The only hitch was a slight flat spot at 7500 rpm (most likely due to the Akrapovic exhaust's 4-into-1 design, versus the stock 4-into-2-into-1 setup), but we'll gladly put up with that for a nine-horsepower increase.
Cook entrusted Traxxion Dynamics (770/592-3823; www.traxxion.com) with upgrading his 6R's suspension. The stock KYB 46mm conventional cartridge fork works well, but has an excessive amount of high-speed compression damping, and the effective adjustment range is rather narrow. Traxxion Dynamics performed a complete makeover of the stock fork ($525), which included a thorough inspection/rebuild, the installation of a TD Axxion Valve kit into the stock damping cartridge, reshimming of the stock rebound mechanism, a Rebound Needle kit that improved the adjustment range, and a pair of heavier-rate fork springs.
Upgrading the brake performance of the older ZX-6R was handled by DP's RDP racing brake pads. We were highly impressed by their improvement in feel and power over the stock pads.
Max McAllister at Traxxion Dynamics feels that the stock 6R shock isn't cost-effective to rebuild/revalve, so he recommends replacing it with an aftermarket unit. Cook wanted complete adjustability (including ride height) and performance for his semi-track-day Kawasaki, so he splurged on a Penske 8981 remote-reservoir shock tuned by TD ($775).
The resulting suspension performance was a night-and-day difference from the stock components. The ride was firmly controlled over the bumpy, faster sections of the Streets course, yet plush over smaller pavement ripples. Midcorner bumps didn't result in upsetting the chassis like they would with the stock suspenders, and weight transfer under braking and acceleration was kept to a minimum. In fact, we preferred the modified, older ZX-6R suspension to the '03's more modern componentry.
Traxxion Dynamics massaged the older ZX-6R's conventional cartridge fork, revalving the damping rates with the company's Axxion Valve, plus heavier-rate fork springs and an overall refresh/rebuild.
Although the stock '02 Kawasaki's six-piston-caliper brake setup is more than adequate, the stock brake pads lack any feel and require high lever effort for good stopping power. We replaced the stockers with DP's sintered-metal RDP racing brake pads ($37; www.dp-brakes.com, available at your local dealer), and transformed the older 6R's binders into race-ready items possessing fantastic power, progressiveness and feel. A set of Spiegler's braided-steel brake lines ($109.95; www.spieglerusa.com; 937/291-1735), and a 42-tooth rear Sunstar sprocket (two teeth lower than stock) completed the performance upgrades.
We'd seen impressive gains on an '00-model R1 with Yoshimura's RS-3 Duplex exhaust, and our '98 Yamaha was no exception. Build quality on the Yosh system was pretty stout for a stainless-steel exhaust.
'98-'99 Yamaha YZF-R1 Mods-Untapped Potential
Although the total amount of upgrades between the '98 and '02 generations of the Yamaha R1 are staggering, the majority are centered around the chassis and handling. The 998cc four-cylinder engine's basic design has stayed the same, with the biggest change being the addition of electronic fuel injection in '02. Coupled with updates to the EXUP exhaust-valve mechanism (moving the assembly farther forward in the exhaust path, splitting the unit into the two secondary collectors of the 4-into-2-into-1 exhaust system, a lighter servo motor, etc.), the latest-generation R1 pumps out 136 horsepower.
We'd already seen fantastic results with Yoshimura's RS-3 Duplex stainless-steel exhaust on the Y2K Yamaha (see the pipe sidebar in the December '00 "Bike of the Year" test), so we decided to see if we could duplicate the results with our '98 test mule. To get carburetion dialed in, we installed a Factory Pro Tuning Components jet kit ($129.95; 800/869-0497; www.factorypro.com), and the company's BMC race air filter ($89.95).
Replacing the stock Yamaha pads with DP's RDP racing brake pads provided a tremendous improvement in the braking performance of the '98 R1. Fantastic feel, power and progressiveness was the norm from the DP units.
As expected, the '98 R1 responded well to the Yoshimura exhaust, pumping out an impressive 141 horsepower, an astounding 14 horsepower increase over stock. There was a slight loss of power down below 4500 rpm due to the lack of an EXUP valve with the Yosh exhaust, but everywhere else in the powerband, the modified R1 towered over the stocker. In fact, it sports a definite advantage over the stock '03 unit's 135.7 horsepower. However, the crisp response from the EFI fuel delivery of the '03 model gives it better acceleration from lower rpms. We also had a problem with a slipping clutch in our '98 test unit, due to the bike being stored for a long period; the clutch plates were dry from non-use and quickly destroyed themselves-R1 owners should take note.
The stock '98 R1 suspension components perform adequately, but after riding the newer version, it was clear that their damping and spring rates needed revising. We sent the fork and shock to Race Tech for a thorough upgrade.
We used Factory Pro Tuning Components' jet kit and BMC air filter to get the fuel curves dialed in for the Yoshimura exhaust. | 
In addition to revalving/rebuilding our stock '98 R1 rear shock with a Gold Valve unit, Race Tech also equipped the shock with its new machined-aluminum Spring Preload Conversion kit that switches the stock ramp-type preload collar to a more precise threaded unit. |
Although it's an inverted cartridge fork, the stock '98 Yamaha R1 unit actually depends on old-style orifice damping instead of the modern (and superior) shim-style damping. Race Tech fully modified our R1 fork with its Gold Valves (plus heavier rate springs and a complete rebuild) to make it behave the way it should. | |
A big problem with the stock R1 fork is that even though it is a cartridge-type assembly, the piston design depends on orifice-style damping, which produces some of the same problems facing an older damping-rod-style fork. This includes excessive high-speed compression damping when hitting large bumps at speed, and inconsistent damping rates; the fork springs are also too soft.
Race Tech (909/279-6655, www.racetech.com) installed both its Gold Valve and Rebound Gold Valve in the fork's cartridge (to replace the stock unit's dependence on orifice damping for both rebound and compression), and fitted heavier-rate fork springs during the complete overhaul ($549.97). The stock shock also received Race Tech's Shock Gold Valve and reservoir cap (which prevents leakage common to the stock unit that can result in a loss of damping) along with the rebuild ($289.99). The shock was also fitted with Race Tech's new Spring Preload Conversion kit ($69.99) that ditches the stock steel stepped preload ring in favor of a more precise threaded adjustment collar with a nifty machined-aluminum adapter assembly.
The resulting performance of the modified '98 suspension was a major improvement. The overall ride was well controlled during all aspects of our racetrack testing, absorbing big hits far better while remaining compliant over smaller bumps. In fact, we noticed a definite improvement in front-end behavior compared to the '03 R1, especially in the faster turns. We also updated the front brakes with a set of DP RDP racing pads. As on the Kawasaki, the sintered metal units provided outstanding power, feel and progressiveness, and were clearly superior to the stock brakes.
This article originally appeared in the October, 2003 issue of Sport Rider.