If there is one the man who knows how to optimize every last performance of a planar tracker is Richard Pollock. The man was called Mule has been building (and racing) them long before Bike EXIF was conceived and has built some of the most coveted trackers to ever grace these pages. So it’s no surprise that his latest creation—a full-blown thug flat road racer—is a great achievement.
If you’re not familiar with the American Grand National Hooligan Championship, it’s a flat-track race for amateurs who ride street bikes that feature high jumps. The rules are simple; you can run any street-legal production bike over 649cc, with an open book of engine, swingarm and wheel modes. But you can’t cut and weld the steering stem to change the shape, and you can’t change the shock mounts on the side of the frame unless they’re bolt-on.
There is also a minimum weight limit of 370 lbs, and each bike needs to have a wheelbase of at least 56 inches. From there, each rider must find creative ways to make their bike go faster and turn left harder. Luckily for Mule, he’s been around long enough to know all the solutions.
“Having raced the Hooligan class every year since 2018 on a Sportster-based bike, I decided to build the most class-legal bike for this year,” he told us. “With the restrictions, my goal is to break the minimum weight rule and get to the point where I have to add more weight.”
Mule started by sourcing the Buell X-1 Lightning from eBay, chosen specifically for its main frame ring. “It’s 10 lbs lighter than the lightest Sportster frame and has a removable cast aluminum subframe that I wouldn’t have used anyway,” he explains.
With the Buell stripped down to its bones, the Mule began to work his magic. First, he fabricated a lightweight chrome-plated swingarm and subframe, with shock mounts on top. A friend and old colleague from his days working in the aerospace industry helped by 3D printing shock absorber prototypes until the design was perfect.
The mounting system uses titanium plates, which are bolted to the top end of a custom Penske shock. It’s a trick setting, but it distracts from an even tricker modification lurking underneath.
“In the original Buell street bike, the engine and cast aluminum swingarm shaft were rubber-mounted,” Mule explains. “The engine is now securely mounted, combined with the billet swingarm and rear engine mount allowing for complete adjustment of the engine position within the frame. Front, back, up, down and axial rotation; bam, how do you like me now?
At the opposite end of the bike are Mule Motorcycles swingarms gripping a Yamaha R6 fork, equipped with JJ Flairty steel extension covers. The wheels use Durelle Racing hubs, Sun rims, stainless steel spokes and Dunlop DT4 tires. The rear brakes use Beringer calipers and rotors, the front brakes are mounted on Mule caliper mounts.
The rear hub also has a custom bolt inside that not only allows for easy shifting, but also allows the Mule to ‘flip’ the rear wheel between races. The idea is to ensure even wear across the tread, as flat grooves always burn the wrong side of the rubber.
Mule had a list of engine mods needed to balance power and reliability, so he threw the book at the factory V-twin. The crankcases and crankshaft were shipped to Dark Horse Crankworks for heavy duty rods, new bearings, balancing and assembly. The top was sent to Branch & O’Keefe in California for custom expansion heads, proprietary pistons, and boring.
Displacement remains 1,200 cc, but the engine now has a Red Shift cam, Jim’s Machining roller controls and Dyna ignition. The original carburetor was rebuilt and modified by Randy Troy Carburetion Specialties. It is supplied with air by a ForceWinder intake and K&N filter, providing more right knee clearance than the OEM air cleaner.
Because hooligan tracks are usually short, the Mule never exceeds second gear. So this race bike uses a two-speed transmission with a Barnett Scorpion clutch, shedding another 12 lbs. “The engine has a lot of torque and a lot of pulling power, so it can easily pull the final gear much higher if necessary,” he adds.
Keen eyes will notice that the bike’s main shell is no longer original. The OEM clutch cable attachment sits very low and tends to come off in low gear. So Mule cut the shell, rotated it about 45 degrees and then soldered it back on, effectively leaving the cable’s attachment point intact.
The modification required fine work so Mule used an EDM wire cutter to strip the main shell. This type of machine is commonly used in aerospace manufacturing because it only removes about 0.01” of material. The front half of the case is also cut and closed, and is equipped with a custom flap.
“The shroud facilitates precise ignition timing, as opposed to the ‘factory caveman’ way of engaging the gear and rocking the wheel back and forth while peaking in one Small inspection hole. “It still takes two people, but it has a very interesting effect. Yes, there are other ways to do it… but this is my way.”
Most notably, this Flat Tracker has the least bodywork we’ve ever seen on a Mule build. The wafer-thin aluminum tank sits atop the frame, made up of several pieces, some of which are radiused from the classic Husqvarna tank. Welded by Mule’s friend Chuck Connell, it held just 1.3 gallons of fuel—enough for the short but intense races the car would do.
The custom oil tank is located further back, with the cap located up front, mounted on a long hose. Both the tank-to-tank hose connection and the tank vent pipe are located inside the frame — so there’s nothing to get in the way of the rider’s feet.
Finishing touches include a muscular two-into-one exhaust, a fiberglass tail section by Competition Sheet Metal and handcrafted cushions by Corbin. The cockpit is a typical Mule — filled with only the essentials and extremely tidy.
But the coolest aspect of this build is the way the minimalist bodywork adds just a touch of zest to the beast, unapologetically showing off its mechanical nature. Designed by SBK Paint, this is a no-nonsense paint color for a no-nonsense machine.
motorbike mule | Instagram | Image by Bart Cepek
