(This article was originally published in the April 2001 issue of Sport Rider)

The voice on the other end of the telephone had that familiar, unmistakably maniacal tone to it.

“Kent. This is Lee. Hey…you gotta ride this bike that I’ve built. It is the s**t, man.”

I immediately knew it was none other than Lee Shierts, a racer and tuner whom I've known since my club roadracing days at California's Willow Springs. Shierts has a history of creating all kinds of fire-breathing, two-wheeled beasts that tweak the rules when it comes to traditional means of construction. His resume includes everything from a 170-horsepower, methanol-guzzling Suzuki GSX-R1100 back in an early Motorcyclist "Superbikes from Hell" competition, to a monster GSX-R750/1100 hybrid Formula USA roadracer he christened "Scud," after Saddam Hussein's aging, but effective missiles used in the Gulf War (SR, October 1998). Shierts' reputation for ultra-fast, high-horsepower machinery meant his boast wasn't just idle trash talking.

Lee Shierts' Suzuki GSX-R600 Hayabusa
Pounding out 8-second quarter-miles, Lee Shierts' GSX-R600 comes with a 218-horsepower Hayabusa motor stuffed inside, making this an insane sleeper.Tom Riles

“So, um…what did you build this time?” I asked, with a hint of both anticipation and trepidation.

"Heh heh heh," he cackled (sounding not too dissimilar to the infamous chuckle from Beavis and Butthead cartoons), "I've taken a Suzuki GSX-R600 and stuck a 220-horsepower Hayabusa motor into it." OK…just what your average, everyday rider needs. Leave it to Shierts to think of the unthinkable.

Formerly based in San Diego, California, and now residing in Charlotte, North Carolina, the affable 35-year-old racer has honed his power craft through many years of experience, including 21 years of racing. “I started doing [performance work] when I was racing dirt bikes back in the late ’70s,” he recalls. “I started my own shop on my 21st birthday; I used to run around in my truck to people’s houses to repair their streetbikes…kind of a mobile service.” Unlike many tuners who apprenticed under someone or had formal schooling, Shierts learned most of his porting and tuning tricks through the time-tested method of trial and error. “I ported my first two-stroke cylinder in the sixth grade,” he remembers, “and did my first cylinder head in 1983.” The dyno has been his measurement device of choice, “I had a flow bench for a while, but it was often misleading.”

Lee Shierts' Suzuki GSX-R600 Hayabusa
Dr. Franken-Shierts aboard his latest creation. Shierts has been racing for more than 21 years, and modifying engines for nearly the same amount of time. He also survived a near-fatal street accident over a year ago.Tom Riles

Shierts’ roadracing history includes several class championships at Willow Springs, which led to his becoming a continual front-runner in the Formula USA series (when the rules were basically unlimited). He even did a year in AMA 250 Grand Prix, finishing a credible fourth place.

Shierts now runs Lee’s Performance Center just outside of Charlotte, (704/599–1507; www.leesperformance.com) which does a thriving business building mostly big-horsepower engines for the dragracing contingent—the majority of whom compete in uh…“non-sanctioned” events. His facility is chock-full of sportbikes with heavily modified motors and extended swingarms that stretch the limit of street legality. In this environment, it’s no surprise that one of the bikes most frequently brought in for engine modifications is Suzuki’s GSX1300R Hayabusa. “I’ve probably ported over 40 Hayabusa cylinder heads already,” says Shierts.

Lee Shierts' Suzuki GSX-R600 Hayabusa
My best run on the Scud III: an 8.725-second at 156.16 mph quarter-mile pass. It was also my first eight-second run, which is a hell of a lot harder to accomplish than you might think.Tom Riles

This led to the genesis of the GSX-R/ Hayabusa creation I was about to ride. Shierts' original hybrid racebike was a GSX-R1100 motor stuffed into a GSX-R750 frame, followed by one that used an 1100 motor in a 600 frame (also nicknamed Scud). So, it was only logical that Sheirts' next project would involve the same big/small philosophy. This time, however, the powerplant switch required some serious fabrication work. "It took a long time to modify the frame to work with the 'Busa motor," relates Shierts. "None of the motor mounts are the same, and there was a lot of cutting and welding of the frame rails to fit the valve cover. And getting the clutch cover to fit when we got the countershaft sprocket location right was a pain." Shierts resorted to an 18-tooth countershaft sprocket so that the chain would clear the swingarm pivot.

With the power this motor puts out, that clearance is probably a good thing. Displacement is bumped up to 1363cc, courtesy of 2mm overbore Wiseco pistons carrying a 13:1 compression ratio. Up top, a Shierts-ported head handles breathing duties with stock injection throttle bodies bored out for less taper. (The stock bodies taper down from 46mm throttle plates to 41mm at the intake tract; Shierts opened the intake tract junction to 45mm.) Inhalation is through shortened velocity stacks—for better top-end power—positioned inside a modified, fully-sealed airbox that uses the fuel tank bottom as its lid. A Dynojet Power Commander with Shierts’ mapping controls the EFI, while a Muzzys titanium exhaust handles the spent gases.

Lee Shierts' Kawasaki ZX-12R
We had a quick chance to try out Lee’s Performance Center customer bikes like a modified Kawasaki ZX-12R with the same engine modifications as Scud III.Tom Riles

The Megacycle cams are Shierts’ own specified “LP1” grind. “They’re not even that big,” he reveals, adding “we made some bigger ones [with more lift and duration] but they didn’t work as well.” APE valve springs keep everything in check, with the Burbank, California, speedshop also handling the lightening and balancing of the crank. Power is transmitted through stock clutch plates housed in a Falicon billet clutch basket, and a MRE air-shifter deals with gearchanges under power. When given the whip, this motor cranks out an incredible 218 horsepower at 10,250 rpm, with 121 foot-pounds of torque at 8000 rpm.

Chassis mods were geared toward drag­racing, but don’t think Shierts didn’t entertain thoughts of roadracing the thing. “The problem is that the engine weighs a ton, creating weight distribution hassles. And the engine is really wide; the alternator cover will be grounding out pretty quick.” Thus, with straight-line competition in mind, the steering head was raked out seven degrees for added stability at speed and a Coby Adams extended swingarm, which can be adjusted to a 67-inch wheelbase, was installed out back. Marchesini magnesium wheels are shod with a Metzeler MEZ3 up front, and the ubiquitous Mickey Thompson street-legal Shootout drag tire in the rear. With two gallons of fuel aboard, Shierts’ beast tips the scales at 425 pounds—can you say power-to-weight ratio?

Lee Shierts' Hayabusa
We also tried out Lee’s Hayabusa, which also had the same engine modifications as Scud III. Both the ZX-12R and Hayabusa were impressive, and ran in the 9.0-second range despite the near-freezing conditions.Tom Riles

We planned to sample that power-to-weight ratio on the street, strip and a top-speed meet at Maxton AFB. But scheduling conflicts killed the top speed idea, and a fast-approaching winter storm scuttled the street ride. In fact, we had to hurry down to Darlington Raceway, in South Carolina, to get the dragstrip runs completed before the snow—yes, snow—started to fall.

After a quick demonstration by Shierts of how to properly heat up the Mickey Thompson Shootout tire, I jumped aboard to get my chance on the beast. I’d ridden bikes with nearly 400 horsepower before, but never at the dragstrip. And since Shierts’ normally aspirated bike garners most of its eight-second quarter-mile elapsed time in the first half of the run, the launch would be critical.

Lee Shierts' Suzuki GSX-R600 Hayabusa engine
The heart of the beast: a monster 1363cc, 218-horsepower Hayabusa motor stuffed into a GSX-R600 frame. Note the fabricated plates welded to the frame spars near the top engine mounts. It’s a very tight fit—you can see the reversed radiator. Shierts says the motor needs to come out in order to adjust the valves. A Muzzys titanium pipe deals with exhaust gases.Tome Riles

And launching a bike like Shierts’ Scud III can be only described as totally insane. The sensation is slightly akin to riding a handlebar-equipped projectile fired out of a cannon. The motorcycle rips off the line so hard that first gear is eaten up in an instant; in fact, the engine has so much torque that launch rpm is a ridiculously low 4000 rpm. Any higher than that is useless, and, as Shierts warned, “it’ll make you just drag the clutch out more and fry it.” My first run resulted in tagging the rev limiter as I frantically tried to get my foot up to the shift lever—I’d forgotten that the bike is equipped with an air-shifter, activated by the horn button. Shierts’ motorcycle pulls with such ferocity that it’s extremely difficult, if not impossible, to get your feet onto the pegs in the first two gears. They’re basically flailing appendages trailing behind as you concentrate on the challenge of keeping the bike tracking straight and hitting the shift button at exactly the right moment.

My next runs improved markedly as I began to get accustomed to the launch’s harsh g-forces and the physical actions necessary to counter them. Without a stepped seat to keep me in place, I had to hold most of my weight with my arms. If I held on too tightly, however, it would affect the steering, and I would veer off onto a dirty, slippery section of the track. During these runs, I also noticed the acceleration didn’t really taper off that much in the higher gears like most bikes—it was almost pulling as hard in fourth gear as it was in first and second.

Lee Shierts' Suzuki GSX-R600 Hayabusa
Shierts bores out the stock Hayabusa throttle bodies for less taper, and fits modified velocity stacks for better top-end power. Jettisoning the stock airbox and using the fuel tank to form the “airbox lid” gained three horsepower, according to Shierts.Tom Riles

Everything finally started to gel on my fifth and sixth runs. I delegated my concentration enough on the required tasks to get a decent launch, and I managed to keep the hurtling projectile I was riding on mostly good pavement all the way down the strip. My sixth and final run before the rain moved in and canceled our festivities was my best: an 8.725-second at 156.16 mph quarter-mile run. Not that bad, considering Shierts’ best on the same bike was an 8.652-second at 162.27 mph blast. And more importantly, I’d finally done my first eight-second quarter-mile pass.

Although we didn’t get to participate in the planned street ride (probably kept us out of jail), I did enough low-speed running on the dragstrip return road to know that Shierts’ bike wasn’t a lurching, coughing beast when off the throttle stops. It idled fine, and putted around the pits at low rpm without loading up or stalling. With this type of horsepower and performance, I have no doubt the bike would do more than 200 mph with the proper gearing. (In fact, Shierts has already gone over 200 with a similarly-prepped Hayabusa at Maxton AFB.)

Lee Shierts' Suzuki GSX-R600 Hayabusa
Peering down the ports of a modified Hayabusa cylinder head reveals some of Shierts’ handiwork. He says the big Suzukis account for a large part of his business.Tom Riles

It’s nice to know there are plenty of people like Lee Shierts out there who think the meaning of too much is not enough. Ingenious minds such as his are always at work devising ways of extracting more power out of the latest sportbike weaponry. And we’re all the better for it. His reply when I commented on the power of his latest motorcycle? “Oh, I’ve built motors that are a lot rowdier than that one. We’ve gotta get you on this one bike….”

Lee Shierts' Suzuki GSX-R600 Hayabusa Swingarm
A Coby Adams swingarm lengthens the wheelbase to a maximum of 67 inches, minus six inches of adjustability. It is also equipped to be used as an air tank for air shifters. A Mickey Thompson Shootout DOT-legal tire puts the power to the ground.Tom Riles