At the heart of every great Harley-Davidson motorcycle is the engine -- here we've got 10 of the greatest of all time.

Harley-Davidson was founded over 120 years ago and has been manufacturing motorcycles in America since 1903. The company's first motorcycle, the Model 1, was designed in 1901 and produced until 1904.

Harley-Davidson's Twin Cam engine powered much of its lineup in the early 21st Century, but had some common major problems that didn't please owners.

Harley-Davidson is one of the most famous and beloved brands on the planet. A dedicated fandom has been buying motorcycles from the Milwaukee-based manufacturer since its inception in 1903. Nearly as ...