Polaris Reveals All-New Indian Thunder Stroke 111 Engine

Indian Motorcycle revealed its all-new Thunder Stroke 111 engine, the first engine developed under its new Polaris Industries ownership and the powerplant for the 2014 model year. According to Polaris, the Thunder Stroke 111 engine has already undergone over a million miles of testing, including thousands of miles of on-road testing.

Polaris deserves some credit for developing an all-new engine for Indian Motorcycle instead of just re-using the 106ci Freedom V-Twin engine used in the current Victory Motorcycles lineup. Instead, Polaris worked to develop a whole new engine in less than two years after the acquisition, providing modern engine technology to the 112-year-old Indian Motorcycle brand.

At 111ci (1811cc in metric) Thunder Stroke 111 engine is larger than the Freedom engine, while its 49-degree V-Twin configuration is just a tad narrower than the Freedom’s 50-degree V. According to Indian, the fuel-injected new engine is air-cooled with an integrated oil cooler and delivers more than 115 ft-lb. of torque, whereas the Freedom engine claims up to 110 ft-lb. of torque.

“Everyone involved in the design of this motorcycle line understands that we are the stewards and caretakers of one of America’s most storied and legendary brands,” says Steve Menneto, Polaris Industries vice president of motorcycles. “We’ve worked tirelessly to retain the truly iconic characteristics of the brand and combine those elements with advanced technologies to deliver a new Indian Motorcycle offering exceptional performance and truly unsurpassed reliability.”

Polaris looked to the 1948 Indian Chief for inspiration in designing the engine. That led to the decision to position the air intake on the left side and have two down-firing exhaust pipes on the right. Other features include finned heads and parallel pushrod tubes with three camshafts and two valves per cylinder with hydraulic valve lifters.

The transmission is a six-speed constant mesh unit with helical-cut gears, a design introduced across Victory’s lineup in 2011. The clutch is a multi-plate wet clutch with integral damper.

“The new Thunder Stroke 111 engine delivers what riders are looking for, and we expect that Indian Motorcycle fans will be inspired by this legendary new power plant as we accelerate toward our full launch in the months ahead,” says Menneto.

The engine will be produced at Polaris’ engine assembly plant in Osceola, Wis., while full motorcycle assembly will be conducted at Spirit Lake, Iowa.

Thunder Stroke 111 Specifications:

Engine Overview
Displacement: 111 c.i. (1811 c.c.)
Engine Torque: More than 115 ft-lbs (160 N*m)
Engine Type: 49 deg V- Twin
Cooling system type: Air Cooled with Integrated Oil Cooler
Idle speed: +/-50rpm 800 RPM
Max Engine speed: 5500 RPM

Valvetrain
Valves per cylinder: 2
Actuation: Three-Cam, Push-rod, OHV
Lifter Type: Hydraulic
Compression Release: Yes
Bore: 3.89 in (101 mm)
Stroke: 4.45 in (113 mm)
Target Compression Ratio: 9.5: 1
Balancer Type: Helical Gear Primary Balancer

Drive Train
Primary Drive: Gear 55/86 ratio
No. of Ratios: 6-speed Overdrive constant mesh
Spur/Helical: 1st Spur, 2-6 Helical
Gear Ratios (overall)
1st: 9.403
2nd: 6.411
3rd: 4.763
4th: 3.796
5th: 3.243
6th: 2.789
Final Drive: Carbon Fiber Reinforced Belt 30/66 ratio
Clutch Type: Multi-plate, Wet clutch, Integral Damper

Fuel Induction system
Throttle actuation: Electronic Throttle Control
Throttle Diameter: 2.13 in. / 54 mm
Fuel Delivery type: Electronic Sequential Port Fuel Injection
Fuel Type: Premium recommended

Lubrication system
Oil Type: 20W-40
Sump type: Semi-dry

[Source: Indian]

By Dennis Chung