When the Cobra Special Projects Division team of Ken Boyko and Denny Berg began planning a bike collaboration, they discussed their affection for the old hot-rod magazines published in the late '50s, and both recalled seeing the lightweight motorcycles with high-performance engines called bobbers. The "Lakester" car culture on the West Coast was all about drag racing and driving at high speeds on the dry lake beds that littered the Southern California deserts. The motorcycles followed with their own stripped-down, nothing-but-the-essentials kind of experience.
Ken and Denny decided to meld a little old with a little new for this bike, consisting of a Sportster motor's bottom end with a knucklehead-appearing top end. Some might be tempted to call the "Knuckster" a bobber, but Denny was quick to point out a difference. "Look, East Coast bobbers were more like dual-purpose bikes, stripped down to compete off-road as well as on. The West Coast, or California, versions were potent drag bikes, usually with no front fender. It was a different kind of performance machine, one with its own specific culture and ethos."
"The last thing the world needed was yet one more custom chopper," added Ken Boyko, Cobra VP. "We had the desire to build a custom motorcycle that we'd actually like to ride, and we were both drawn to those early California bobbers. So the Knuckster became that bike." Though the Knuckster looks like a wonderful restoration of a '50s bobber, it's really all new, including the engine itself.
Harley engine builders in the '40s and '50s found innovative ways to improve their engines, coming up with Frankenstein creations in the search for horsepower and speed. There was the "45 Magnum," which used a Sportster top end. There was the "Shovester," which used a Sportster engine mated to a shovelhead top end. The Knuckster's engine is an S&S Buell engine using parts that make it look like a knucklehead top end. It began life as a 51ci engine and then was punched out to 91 cubic inches with a 4-inch bore and 3-5/8-inch stroker flywheels. High-lift cams (0.555 inch) and an S&S Super G carb add to the horsepower gains. All of that power gets to the road via a Baker six-speed transmission and chain final drive. By the way, that kick-starter pedal is not a functional unit-besides aesthetics, its only purpose is to serve as an exhaust heat shield.