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The FX Project Part 1

We build our Suzuki GSX-R600 test bike into an AMA Formula Xtreme racebike

By Andrew Trevitt
Photography by Adam Campbell

While our geek (left) manned the phone and e-mail to gather all the parts and Corey Neuer (center) did the riding, Eric "E-Money" Nugent (right) assembled the bike and was a huge help at the track.
While our geek (left) manned the phone and e-mail to gather all the parts and Corey Neuer (center) did the riding, Eric "E-Money" Nugent (right) assembled the bike and was a huge help at the track.

Sometimes we just can't help ourselves. It began two years ago when Corey Neuer, test editor at our sister publication Dirt Rider, bought a GSX-R600 and started club roadracing. Soon after, we could count on Neuer showing up on our side of the motorcycle group's floor practically every Monday morning, regaling us with his weekend's exploits. At first we were supportive, offering tips, congratulations for good finishes, and so on. But as the tales grew taller each week and the stories longer, we eventually just...well...stopped coming in on Monday mornings.

We realized that, like a poor puppy sometimes needs to be saved from chasing its tail, we needed to rescue Neuer from, um, chasing his tail. Sport Rider would take him under its collective wing, build a racebike for him and coach him up to speed. The final goal, a sort of coming-out party or prom night, if you will, would be Neuer racing a bike we built in the AMA's Formula Xtreme race at California Speedway, his first-ever AMA race. This is Part 1 of that story, covering the bike--in fact, our 2004 Suzuki GSX-R600 test unit--itself. Next issue, Neuer will tell his side of the story.


Over the course of four months, our '04 GSX-R600 test bike evolved into a full-blown Formula Xtreme racer.
Over the course of four months, our '04 GSX-R600 test bike evolved into a full-blown Formula Xtreme racer.
We started with suspension modifications and basic racebike prep.
We started with suspension modifications and basic racebike prep.
then had the engine hotted up and the bodywork painted .
then had the engine hotted up and the bodywork painted .
We bolted on the 16.5-inch wheels and slicks midway through a track day to better note the differences and make adjustments accordingly.
We bolted on the 16.5-inch wheels and slicks midway through a track day to better note the differences and make adjustments accordingly.
Finally, it all came together for the race at California Speedway .
Finally, it all came together for the race at California Speedway .

These beautiful Attack Performance rearsets offer loads of adjustability for footpeg position.

We decided to go the Formula Xtreme route for several reasons. With the recent downsizing of FX bikes from 1000cc to 600cc, it would be a chance for us to explore what a 600 is capable of with more than the usual Supersport modifications. As well, throwing Neuer into the Supersport or Superstock class would be like putting that lost puppy in a cage of pit bulls; for now, the Formula Xtreme class is the least--shall we say--frantic of the AMA classes.

Picking a starting point was somewhat a matter of availability; with most of the 600s new for '05 and our '04 GSX-R still sitting innocently in the shop, we pounced on the Suzuki. That way, rather than wait for a brand-new bike and even longer for parts to trickle in for the '05 models, we could start immediately. That settled, we began collecting goodies for the little GSX-R.

We'll admit our FX bike is not a full-blown factory-replica mini-superbike, but rather something a club racer could build given a decent budget and resources. You won't see a works hlins Superbike fork, $1800 one-piece billet Brembo brake calipers or hand-grenade horsepower readings on the dyno. We used reworked stock parts where possible, a conservative engine spec and a careful mix of aftermarket goodies to get the most bang (and the least headaches) for the buck. And besides, it's unlikely that the burgeoning AMA racer (that would be Neuer) could take advantage of some of the more esoteric parts available.

The company offers only this hard-anodized finish, which is superior to and lasts longer than colored anodizing.
The company offers only this hard-anodized finish, which is superior to and lasts longer than colored anodizing.

Suspension is traditionally the one setup aspect that takes the longest to dial in, so we addressed the GSX-R's boingers right away. We already had a rear suspension link ($399) from Ammar Bazzaz's BPD (Bazzaz Performance Design, see sidebar), which bolted right on and offers a flatter--and more racing-appropriate--progression curve than the stock linkage. We complemented that with an hlins shock ($1213) with full adjustability: remote spring preload, ride height, rebound damping and both high- and low-speed compression damping. Bazzaz opened up the brand-new hlins and tweaked the internals to better match the linkage, a modification he says is not strictly necessary. While we were on the phone with our friendly Parts Unlimited hlins representative, we ordered up an hlins steering damper ($455), which mounts in the standard position in front of the fork, safe from crash damage.

Inside the fork tubes, we replaced the stock valving with K-Tech compression and rebound valves ($399) from BPD, slid in a set of stiffer K-Tech fork springs ($101) and filled each tube with Maxima fork fluid. The K-Tech setup also replaces the stock compression adjusters at the bottom of each fork leg with "external flow control" valves ($120), which offer a greater range of adjustability. BPD offers an installation service for the fork internals ($200), but it was a fairly straightforward job we managed ourselves with the right tools.

The Brake Tech floating rear disc (left) goes a long way toward reducing rear-wheel drag and unsprung weight, but we had to grind the hanger (above) to clear the bobbins and bolt heads.
The Brake Tech floating rear disc (left) goes a long way toward reducing rear-wheel drag and unsprung weight, but we had to grind the hanger (above) to clear the bobbins and bolt heads.

Attack Performance provided a set of its beautiful triple clamps ($779), which are machined from billet aluminum and offer adjustable offset through the use of eccentric inserts. Installation required pressing the steering stem out of the stock bottom clamp (hint: You need a press to do this), as well as scrounging a fork clamp for the steering damper, as the stock unit mounts to the bottom clamp. It all went together painlessly, and we were able to change trail in less than a half-hour; no doubt professionals could do it in minutes with the slick Attack setup.

Next we turned to the Suzuki's front brakes. Formula Xtreme rules allow the replacement of the entire brake system, including discs and calipers, and originally we wanted to go with a complete Brembo setup. Turns out the only Brembo caliper available to fit the standard Suzuki caliper-mount spacing is the big-bucks machined GP-spec caliper. The cheaper cast units were on the horizon and may be available now, but we decided to stick with the stock calipers. We did have some brake troubles on our stock test bike and had heard reports from several racers about the new-generation GSX-R's brakes fading on the track. Some of that fading can be traced to the aluminum (instead of steel) pistons in the calipers, which, although lighter, transmit more heat to the calipers and brake fluid.

A set of Attack Performance triple clamps accommodate offset changes in 1mm increments and are significantly beefier than stock. We had to improvise for the master cylinder reservoir, but the company offers an ignition switch bracket as an option. We ditched the key switch and wired in a small toggle switch. You can just see the Brembo master cylinder that cured our GSX-R of brake fade, but you can't see the R1 tube in the stock throttle housing that gave a much shorter throw.
A set of Attack Performance triple clamps accommodate offset changes in 1mm increments and are significantly beefier than stock. We had to improvise for the master cylinder reservoir, but the company offers an ignition switch bracket as an option. We ditched the key switch and wired in a small toggle switch. You can just see the Brembo master cylinder that cured our GSX-R of brake fade, but you can't see the R1 tube in the stock throttle housing that gave a much shorter throw.

Our first brake-setup iteration consisted of swapping the stock rotors for a set of Brake Tech's iron Axis Design rotors ($330 each) and matching Ferodo pads. The Axis rotors' innovative design places the buttons that attach the disc to the carrier in a non-load-bearing position, which allows the rotors to be lighter and improves their thermal transfer capabilities. The discs are also cryogenically treated, a process that transforms the molecular structure by cooling the parts down to -300 degrees Fahrenheit. According to Brake Tech, this relieves stress and gives the discs a memory shape they return to after heat cycling. Additionally, the discs are made from ductile iron rather than the traditional gray iron, which allows the use of either sintered or organic pads. (Sintered pads can cause stress cracking in gray iron, and organic pads are usually required.) We used Ferodo's Sintergrip XR racing pads ($60 per caliper) as recommended and provided by Brake Tech.

HEL USA sent a set of its stainless steel brake lines ($164), which feature titanium fittings for light weight without the corrosion problems of aluminum fittings, and we used Maxima's DOT 3/550 brake fluid. We still had some fade problems with this setup, and while we couldn't pinpoint the exact cause, it turns out the stock radial-pump master cylinder is partially to blame. We replaced it with a Brembo forged aluminum unit ($360) from Brake Tech, and that eliminated almost all our fade problems.

Out back, we used another HEL brake line ($82), a Brake Tech rear floater disc ($180) that utilizes stainless steel bobbins on the mounting bolts to significantly reduce drag and a set of Ferodo organic pads ($34).


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