The hlins steering damper...
The hlins steering damper bolts to the stock frame mount and a fork clamp taken from Neuer's stash. You can see here how tall the bottom Attack triple clamp is, with three bolts on each side. We originally ordered a Vortex fairing bracket from LP USA to replace the stock bracket (which doesn't hold the gauges), but it didn't fit; we're still waiting on a replacement from Vortex. In the meantime, this homemade aluminum piece does the job.
Once we had the suspension and brakes squared away, we concentrated on race prep and lightening the GSX-R. Attack Performance anted up with a set of its adjustable rearsets ($436) that are more art than motorcycle parts. Twelve positions of adjustment are available for the footpeg, and the shifter can be adjusted for leverage ratio. The pedals mount using ball bearings, resulting in smooth, precise action with no slop or wear, and the pegs themselves provide much more grip than stock. Likewise, Attack's 50mm clip-ons ($225) are beautifully made and bolted right up. Their design features replaceable tubes, the clamp is hinged and the clip-on can be removed without unbolting the top triple clamp or removing the fork leg; both features are handy in the event of a crash.
A phone call to Lockhart Phillips, which incidentally sponsors the Formula Xtreme class, netted a variety of necessities: Vortex heavy-duty case covers ($170 for the left, large cover and $70 for the starter side) are machined from billet aluminum and protect the engine in case of a tip-over. Proimpact's polyethylene frame sliders ($50) do the same for the frame and bodywork. Both the case covers and frame sliders mounted up with no trouble, and luckily we didn't have to test their crashworthiness. LP's own V2 Speedscreen ($70) sits a bit taller than stock, providing more wind protection and a clear view out the front.
We replaced the stock clutch...
We replaced the stock clutch with this STM slipper clutch ($1050) from Lockhart Phillips, which uses the stock plates and one large diaphragm spring. A ball-and-ramp mechanism deep inside controls slippage under deceleration. It's a must-have for classes that permit it, as it almost eliminates wheel hop on downshifts and makes for blazing corner entries.
Gearing necessities were taken care of by Sprocket Center, which supplied a selection of black-anodized RRP rear sprockets for both the stock and Marvic rear wheels, an RK GXW520 X-ring chain and RRP front sprockets made from case-hardened steel and drilled for lightness. A 520 conversion kit from Sprocket Center with the RK X-ring chain and two RRP sprockets retails for $180.
Instead of doing the engine work ourselves and then having a professional fix our mistakes afterward we went the direct route and shipped the motor off to Grant Matsushima's MPT Racing (see sidebar) for an overhaul and appropriate horsepower massage. Figuring 120 ponies would be in the ballpark for a reliable output, we asked Matsushima to perform a basic supersport prep, along with whatever tricks he had up his sleeve that were within the fairly liberal rules and didn't sacrifice reliability. He delivered, with a 118-horsepower mill that didn't miss a beat over nine days of track riding and racing. Matsushima reported that our 4000-mile test bike "didn't have any weird wear marks, but a lot of the components got replaced because I wanted it to be a fresh motor. They didn't get replaced because they were worn, they got replaced because it's a motor I'm building, and it's a motor that's going to be raced." On top of the freshening-up, Matsushima added a valve job and some mild porting, milled the head and slipped in "some short-duration Yosh cams left over from a couple of projects ago."
118 horsepower is a huge increase...
118 horsepower is a huge increase over the stock GSX-R's output, but in retrospect we should have erred less on the side of caution (read: reliability) and gone for more (read: $$$). While the factory Hondas posted 165-mph trap speeds at Fontana, our project bike could only muster 151 mph.
Exhaust duties are handled by a LeoVince full system ($1358), which is specially designed for Formula Xtreme-spec racebikes with a thin-wall stainless-steel header, titanium collector and a full titanium canister with a larger inner diameter. On the opposite end of the fuel/air combination, we used VP's Ultimate 4 racing fuel ($18/gallon), which provides power levels close to the company's MR9 rocket fuel but at a fraction of the cost. And to keep it all running smoothly and for that last bit of horsepower we filled the crankcase with Maxima's Maxum4 Ultra 0W-10 synthetic oil ($13/liter) that we know is good for a couple of horsepower.
Putting that power to the ground is a set of Marvic cast magnesium wheels from Yoyodyne and Dunlop 16.5-inch slicks. The Marvics alone cut several pounds from the GSX-R, and the rear wheel has a reasonably durable cush drive for which RRP makes sprockets to fit. Both wheels were direct replacements for the stockers, with the rear wheel's spacers captive to make wheel swaps much easier. We used medium-compound Dunlops for most of the project, in 125/80 KR106 and 195/75 KR108 sizes and constructions. According to Dunlop's Jim Allen, serious Formula Xtreme racers use this 16.5-inch setup, but a case can be made for swapping the stock 5.5-inch-wide rear wheel for a 6.0-inch hoop and using 17-inch slicks. Development in 17-inch slicks is progressing due to their use in the AMA's Superstock class. In any event, grip was never a problem for our bike.
We borrowed the radiator from...
We borrowed the radiator from Neuer's GSX-R750, which is significantly larger than the stock 600 radiator and lowered coolant temperatures around 20 degrees Fahrenheit. Note the carrier design of the Brake Tech Axis rotors, the suspension potentiometer for the data-acquisition setup and the K-Tech replacement compression damping adjuster.
European Motorcycle Accessories provided a Translogic Quickshifter ($615), which took some time to install. Almost all the connections--including the interrupts for the fuel injectors--required cutting stock wires and splicing in spade connectors. Even though we soldered and taped each spade connector, the setup was still a constant source of worry; we'd much prefer a unit that simply plugs into the stock harness or injector connectors. The Quickshifter itself worked fine, requiring almost no setup or adjustment, and it provided quick, crisp full-throttle upshifts. A programmable shift light is also available and can be wired in, as can a dashboard with a gear indicator, tach and lap timer.
The entire package is wrapped in a set of Hotbodies Racing fiberglass bodywork ($650). The flexible bodywork came primered, but we had to install the hardware and fix a few blemishes in the finish before having it painted. The fairing and seat mounted up easily enough and proved quite durable over the course of the project. Airtrix applied the incredible yellow-and-black paint scheme, and Imagine It graphics, our usual supplier for quality custom stickers, made the Sport Rider vinyl-cuts.
With no Ultimate 4 in the tank but all the data-acquisition equipment in place, the Suzuki weighs in at 367 pounds, 35 pounds less than stock but slightly porky for the 350-pound minimum weight limit for the class. Removing the Drack data-acquisition box (and its related sensors) and ditching the stock starting system, a modification Matsushima recommends, would most likely put the GSX-R as close to the minimum weight as we'd want to tread. For the complete tale of Neuer's first-ever AMA race and to find out how our bike fared in the Formula Xtreme race at California Speedway, check out Part 2 of the story in our next issue.
This rat's nest of wiring...
This rat's nest of wiring is courtesy of the various sensors for the Drack data-acquisition setup and the plug-ins necessary for the Translogic Quickshifter. Here you can see the main unit for the shifter, as well as the gyro for the data-acquisition setup.
More wiring! The Drack unit...
More wiring! The Drack unit hides in the tailsection, and the regulator/rectifier was relocated on top to make removing the bodywork easier.
Some parts belong in a gallery...
Some parts belong in a gallery rather than on a racebike: The Attack rearsets and BPD suspension linkage are precision-machined, work flawlessly and look ultra-trick. Another data-acquisition potentiometer nestles beside the ultra-adjustable hlins shock. The pressure sensor in the shift
Final-drive components were...
Final-drive components were taken care of by RRP sprockets and an RK chain; RRP's black-anodized aluminum rear sprockets held up fine and are ultra light, and the X-ring chain hardly stretched at all over the course of the project. Airtrix gave the Marvics a thin (for lightness--you'd be surprised how much weight paint can add) black powdercoating. Check out how tall the sidewall is on that fat 16.5-inch Dunlop slick!
This LeoVince canister is...
This LeoVince canister is much shorter than the company's standard silencer and is part of the full system specially designed for Formula Xtreme bikes.
We used our Drack data-acquisition...
We used our Drack data-acquisition setup to monitor speed, rpm, throttle position and suspension travel. It helped immensely with bike setup and helped us coach Neuer with his riding.
A Factory Pro Teka Suzuki...
A Factory Pro Teka Suzuki Fuel Injection tool ($595) was used to adjust mixture in the stock ECU; we were able to complement the STM slipper clutch by richening closed throttle fueling to further reduce engine braking.