1933 Indian Four
Claimed power: 30hp (est.)
Top speed: 75mph (est.)
Engine: 1,266cc (77.21ci) air-cooled inline four
Weight: 495lb (225kg)
Fuel capacity: 4.6gal (17.4ltr)
Price then: $395
Price now: $20,000 - $60,000

In the early days of cars, the Ford Model T was appreciated as an economical workhorse, a simple automobile with a basic four-cylinder engine. Certainly there were bigger and more powerful engines in far sexier cars, such as the impressive V-12 in the 1916 Packard Twin Six.

The situation was much the same with classic American motorcycle manufacturers. Stout and sturdy single- and twin-cylinder engines in numerous makes of two wheelers could be likened to Ford’s humble four-banger. However, while the four was at the bottom of the ladder in the land of automobiles, a four-cylinder engine in a motorcycle was the pinnacle of power in the late teens — and for the two decades that followed.

A four-cylinder motorcycle like Gary Phelps' 1933 Indian Four was a luxury item for a private owner, as they were usually much more expensive than their single- and twin-cylinder counterparts. Generally, only the wealthy or police forces — where the machines were lauded for their power and ease of handling — were readily able to afford and operate four-cylinder bikes.

Watch a video of Jay Leno talking about his 1933 Indian Four 

History of the four
Ace, Cleveland, Gerhart, Henderson, Indian, Militaire and Pierce all made four-cylinder motorcycles in North America, and each of these ran an inline four with the engine placed longitudinally in the frame, as opposed to the more common transverse placement of four-cylinder engines we’re used to today, starting with Honda’s revolutionary CB750 in 1969.

There were other builders of four-cylinder bikes around the world, although not all had their cylinders inline. Britain’s Ariel made a square four, while Brough Superior constructed an experimental “stacked” flat-four (it had pairs of opposed cylinders, one on top of the other) and Matchless a V-four. Other fours included the Vauxhall inline four, the Wilkinson inline four and the Wooler flat four. Of all the British concerns, only Ariel’s Square Four (built from 1931 to 1959) had any real success. On the Continent, FN and Nimbus sold inline fours, as well.

The Indian Four was built by the Springfield, Mass., company from 1927 to 1942. This particular example is a 1933 Indian Four, commonly known as a Model 403, and it currently resides with Gary Phelps in Ventura, Calif. Tracing the roots of the Indian Four reveals ties to two earlier American builders of four-cylinder motorcycles — Henderson and Ace.