Harley-Davidson motorcycles are pretty famous for their big, chugging, powerful engine sounds. Here are the most aurally ...

Take, for instance, this rowdy Knucklehead chopper from Custom Works Zon. Yuichi Yoshizawa and Yoshikazu Ueda took a 1947 Harley-Davidson powerplant and used it as the basis for their build.

Jay Leno's 1936 Harley-Davidson Knucklehead had already been sitting for years when he bought the it, and the former Tonight Show hostleft it resting for a few more decades in his own garage ...