Polaris, owner of Indian since spring 2011, said its goal in designing the engine was “to capture the iconic design and styling aspects of the 112-year old brand’s most historic models and fuse that heritage with state-of-the-art technology and progressive design elements.”
Polaris researched the complete history of Indian Motorcycle power train development by reviewing volumes of historical documents, test-riding vintage motorcycles, and studying and dissecting an array of Indian models.
Specs for the new engine, according to Polaris:
- Engine displacement: 111 cubic inches
- Torque: More than 115 ft.-lbs.
- Architecture: 49-degree V-twin, air-cooled with integrated oil cooler, finned heads, a left-side air intake, a down-firing exhaust system and parallel pushrod tubes, with the proportions and layout familiar to Indian Motorcycle fans
- Crankcase: Unit design featuring a high-capacity semi-dry-sump oil system, oversized oil radiator
- Timing system: Three camshafts, pushrods, two valves per cylinder acting through maintenance-free hydraulic valve lifters, forged crankshaft
- Fuel system: Electronic sequential port fuel injection, electronic throttle control
- Compression ratio: 9.5
- Transmission: Six-speed overdrive, constant mesh, helical gearbox
- Clutch: Low-effort, multi-plate wet clutch, aluminum basket, integral torsional damper
Polaris said it performed more than 1 million miles of testing, including dyno testing and hundreds of thousands of miles of on-road testing.
The Thunder Stroke 111 is built in Osceola, Wis., at the Polaris Industries Engine Assembly Plant, with future full-unit motorcycle assembly taking place in Polaris’ production facility in Spirit Lake, Iowa.
Indian is now showcasing the Thunder Stroke 111 in a “Spirit of Munro” streamliner custom-built in honor of Burt Munro’s “Munro Special,” portrayed in the 2005 movie “The World’s Fastest Indian.”
Posted by Arlo Redwine. Photos courtesy Polaris.