Harley-Davidson has dropped their 1994 patent application to trademark their engine sound (I noted this in April). Their VP of Marketing says: “frankly, we’re tired of throwing tens of thousands of dollars out the window on litigation.” They have not lost any business from imitators, and I doubt they will. Having a “trademarked sound” is more of a cachet item than a business need for them. No Harley enthusiast is going to settle for a Honda, even if it does go “potato-potato” properly.