1936 Indian 436 Upside Down Four Motorcycle
Indian’s Powerful Inline Air Cooled 4 Cylinder Engine
Inverted Exhaust-over-Intake Valve Configuration
Large exhaust heat shield attempted to protect riders’ leg from burns
Updraft carburetor
This restored 1936 Indian Model 436 represents the second generation of Indian 4 Cylinder motorcycles, intended to eclipse the performance of Harley Davidson’s new “knuckle head” overhead valve V twin engines with improved comfort and speed. Indian was not the first company to utilize a fore and aft inline 4-cylinder engine, a design dating back to the Pre-WW1 era.
In 1927 after acquiring the ACE motorcycle company along with the engineering talents of Arthur Lemon, Indian became the last US motorcycle manufacturer to feature an air cooled inline 4, the likes of which continued up until the Second World War.
Based on Henderson and Ace motorcycles, the output of early Indian 4s provided smooth tractable power that became popular with police departments but lacked acceleration and speed compared with Indian’s Sport Scout V twin engines. In 1936, Indian attempted to address this shortcoming by re-engineering the engine placing overhead exhaust valves above the side-oriented inlet valves in an attempt to increase power and improving cooling airflow to the exhaust valves. Unfortunately, only one of the two intended outcomes came to pass. While the engine’s horsepower saw a moderate increase, the placement of the exhaust high on the engine caused a significant amount of heat directed at the rider’s leg and required an awkwardly styled cover to be placed over the manifold to prevent serious burns to the operator.
Additionally, the rear cylinders received inadequate airflow to the cooling fins, adding to rider discomfort. As this was considered a luxury motorcycle with a limited audience due to the economy of the time, the “upside down” engine changes were to last only two model years, with Indian resuming the traditional intake over exhaust configuration in the 1938 model year.
This 78 Cubic Inch 1936 Upside Down Four has undergone an extensive 100-point restoration by a marque expert. It is a rare early edition model 436, as evident by the exposed exhaust valves, and it features a Marvel updraft carburetor, robust leaf-spring front fork, 3-speed hand-shifted gearbox and a 6-volt electrics package. A quick and elegant motorcycle, this restored 1936 Upside Down Four is finished in black and maroon paint with gold accents. It’s an Art Deco masterpiece and a testament to Indian’s willingness to push engineering boundaries.
Specifications:
Engine: 77.1 Cubic Inch (1265cc) inline 4-cylinder overhead exhaust valves, side intake valves
Transmission: 3-speed, Right-hand shift, left-hand throttle(intentionally the opposite of the Harley Davidson), foot operated clutch, chain drive
Performance: 35 Horsepower
Top Speed: 95 mph
Weight: 515 lbs wet
Brakes: Drum front and rear