The MotoAmerica's King of the Baggers competition has been a resounding success, featuring heavily customized Harley-Davidson Road Glides and Indian Challengers. Whispered rumors suggest horsepower figures ranging from 165 to 185, while these bikes, mandated to weigh at least 620 pounds, have impressed many with their ability to set blisteringly fast lap times.
It was about time for Harley enthusiasts to realize that while being cool is enjoyable, being fast can be equally exhilarating.
Now, the Motor Company introduces the CVO Road Glide ST with the potent 121 HO engine—where "HO" stands for High Output—delivering a claimed 127 horsepower at 4,900 rpm and 145 lb.-ft. of torque at 3,000.
This engine differs from standard 121 engines by foregoing variable valve timing in favor of a camshaft with longer, race-inspired valve timing, reaching a redline of 5,900 rpm.
To understand the significance of these enhancements, it's essential to recall Harley's traditional reputation for robust low-end torque, necessary for propelling its hefty mass. Traditionally, torque peaked early and tapered off as revs climbed, owing to brief valve timings reminiscent of classic VW Beetle engines—intakes opening at top dead center and closing at bottom dead center. However, such short valve timings restricted airflow at higher engine speeds, leading to diminished performance.
With the evolution of the Interstate Highway System, riders demanded increased cruising speeds and passing power. Engine displacement grew over the years to meet these demands, yet Harley's signature low-end torque remained unchanged.
Variable valve timing (VVT) emerged as a solution for enhancing acceleration during overtaking maneuvers. VVT adjusts the phase angle between the cam and crankshaft as engine speed rises, optimizing valve timing for different rev ranges.
It's plausible that insights gleaned from Harley's King of the Baggers racing team, revitalized with a factory-backed effort, have informed the development of the CVO Road Glide ST. This likely involves a camshaft design that advances intake opening before top dead center, facilitating smoother cylinder filling, and delays closure after bottom dead center, maximizing intake duration for improved performance across the rev range.