Motorcycle specifications IndianFour type 401 1928 The Duesenberg of motorcycles

The story of the Indian Four model 401 begins with a strategic decision by the brand. At the end of 1926, the company acquired all the assets of the bankrupt Ace Motor Corporation. This acquisition was not a simple business expansion, but a targeted maneuver to seize both a proven engine design and the engineer behind it. The engineer in question, Arthur O. Lemon, had perfected the original Ace in-line four-cylinder engine designed by William Henderson. By hiring Lemon as chief engineer, Indian not only obtained the rights to the engine design, but also the expertise to develop it.

Indian's main motivation was to create a flagship model to compete directly with its long-standing rival, Harley-Davidson. The Ace's powerful 4-cylinder engine was seen as the ideal candidate for this role. Initially, Indian continued to produce the motorcycle under the Indian-Ace name, with minimal changes, mainly cosmetic, such as the application of the "Indian red" corporate color and the addition of the Indian Chief emblem. By 1928, however, the 401 model had taken the place of the Indian-Ace, marking the beginning of the integration of this design into the Indian range.

The competitive landscape and the "big three

The launch of the Indian Four took place against a backdrop of fierce competition between the "big three" of American motorcycling at the time: Indian, Harley-Davidson and Excelsior-Henderson. This rivalry propelled the companies to constantly improve their products, from the race track to the dealerships. While Indian and Excelsior-Henderson dominated the 750cc motorcycle market with their respective Scout and Super X models, their larger-displacement machines, such as the Indian Four and Henderson Four, were recognized for their aesthetic appeal and technical advances.

The stock market crash of 1929 turned this landscape upside down. Sales fell dramatically, pushing all three companies to the brink of bankruptcy. The way each handled this crisis reveals much about their corporate vision. Harley-Davidson survived by selling its old tools and parts to a Japanese importer, an operation that helped finance the manufacture of Rikuo motorcycles under license. Ignaz Schwinn, owner of Excelsior-Henderson, made a radical decision. Foreseeing a prolonged decline, he opted to withdraw from motorcycle production to concentrate on his more stable core business: bicycle manufacturing.

Indian's survival during this period is largely due to its major investor, E. Paul DuPont. Rather than liquidate his investment, he bought back a majority stake in the company, an action that paradoxically led to Indian's most profitable period, from 1930 to 1945. This willingness to maintain production, particularly for a luxury model like the Indian Four, testifies to Indian's long-term commitment to engineering and performance, at a time when other American manufacturers were giving up.

The Model 401: a technical dive

The 1928 Model 401 is the first Indian Four and forms a solid foundation on which the brand has built its heritage of luxury and performance.

The heart of the Indian 401 is a 1265 cc in-line four-cylinder engine. It features an "F-Head" or IOE (Inlet Over Exhaust) valve configuration, meaning that the intake valves are overhead, while the exhaust valves are side-mounted. The 1928 model 401 had a bore of 69.8 mm and a stroke of 82.5 mm. This engine produced around 30 hp in the late 1920s, a figure that climbed to 40 hp ten years later.

In August 1927, Indian announced the 1928 models, including the Indian Collegiate Four, which incorporated a new high-pressure lubrication system. This improvement was aimed at increasing top speed and engine reliability, demonstrating the brand's commitment to perfecting the original Ace design. The engine is fed by a Schebler carburetor and the ignition system is provided by a Splitdorf magneto or a battery-powered system.

A rapidly changing chassis

The Indian 401 has inherited most of its cycle components from the graceful and agile 101 Scout, including the fuel tank, seatpost, rear frame and mudguards. The frame is a single tube, as opposed to the double-tube frame that later appeared on the 402 model. To compensate for the increased weight of the four-cylinder engine, an auxiliary leaf was added to the front spring.

Model 401's suspension consisted of a leaf-and-arm front fork and a rigid rear. Indian replaced the Ace's trailing-arm fork with its own design to ensure more harmonious integration with the rest of the brand's range. Braking was provided by front and rear drum brakes, the addition of a front brake having become standard in early 1928.

The 401 was equipped with a 3-speed transmission, with manual shifting.

A lifetime of evolutions from the 401 to the 442

The Indian Four did not remain static. The company continued to evolve it, learning from its own innovations and those of its competitors.

As early as 1929, Indian introduced the 402 model, which represented a significant advance over the 401. Engineers improved the engine by increasing the number of crankshaft bearings from three to five, a crucial upgrade that greatly enhanced durability and reliability. The new Scout-inspired double-tube frame was also introduced, improving chassis rigidity.

The "upside-down" engine fiasco

Indian's engineering sometimes took risks, as evidenced by the 1936-1937 models, which were equipped with an "upside-down" engine. In this EOI (Exhaust-Over-Inlet) configuration, the valve positions were reversed, placing the exhaust valves above the intake valves. The aim was to increase power and improve airflow for better cooling.

Although the engine did experience a slight increase in power, placing the exhausts high up created a major comfort problem for the rider, directing an excessive amount of heat towards his inner leg. A heat shield was necessary, but it wasn't enough to appease customers. The bike was considered an Art Deco masterpiece, but sales plummeted due to this design flaw. Indian finally abandoned the experiment in 1938, reverting to the original IOE configuration, "much to the delight of Indian customers". Another curiosity of this production period was that the bike was equipped with a right-hand gearshift and a left-hand throttle, which was intentionally the reverse of the controls used by Harley-Davidson. This decision illustrates the competitive nature of the industry at the time, where even ergonomic choices were statements of rivalry.

The ultimate: the 1940 Model 440

The development of the Indian Four reached its apogee with the introduction of the 1940 Model 440. This version featured iconic skirted mudguards, a raised exhaust and multiple design modifications, including a heavier frame and spring-loaded rear suspension. This model cemented the Indian Four's reputation as the pinnacle of American luxury and engineering. Production ceased in 1942 due to the war effort.

The prestige experience

From the outset, the Indian Four was hailed for its comfort and smooth running, thanks in part to its in-line engine, which critics described as "quiet and smooth, like a car engine". It wasn't designed as a powerful, comfortable motorcycle for long highway journeys. It was capable of speeds of 145 to 160 km/h, making it faster than most cars of the time.

M.Bi. - Photos D.R.
Image credit: Yesterdays.nl