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'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 has just marked the last Evo engine to roll off her belt – and to say the industry’s got mixed feelings on the matter is the understatement of the year. Do you remember the first bike ...