Here’s another choice feature in the Hagerty time-lapse rebuild series: the classic Harley-Davidson Sportster Ironhead V-Twin.

We enjoy sharing the Hagerty Redline Rebuild video series here at Mac’s Motor City Garage. The time-lapse format allows us gearheads to see many of our favorite engines inside and out, up close and personal, in just a few minutes—and without crushing our knuckles or making a total mess of the garage, either. This episode features the venerable Harley-Davidson Sportster V-Twin motorcycle engine of 1957 through 1985, also known as the Ironhead Sportster.

The original Sportster V-Twin, produced in a variety of displacements from 883 to 1200cc, shares a number of features with its H-D Big Twin brother, including the distinctive 45-degree bank angle, the flywheel-style crank assembly, and the chain-drive primary setup. And the Sporty also employs the same basic cylinder-head layout as the 1966-84 Shovelhead Big Twins. But there are some obvious variations from the classic Big Twin theme, too: Note the unitzed crankcase and transmission casting, a shocking innovation for an American bike back in 1957 when the Sportster was introduced. And check it out, there are four camshafts, one for each valve—a configuration used on the old H-D flatheads back when dinosaurs roamed the earth. Enjoy this fascinating look inside one of the classic motorcycle engines.