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.

That’s the sort of collaboration which led to the creation of this rad Iron 883 bobber, pieced together by Gasoline Motor Co. for spiced rum producer Sailor Jerry. Aside from some broad guidelin ...