Indian Unveils Liquid-Cooled PowerPlus 108 V-twin

Indian PowerPlus 108 V-twin
Indian’s new liquid-cooled PowerPlus 108 V-twin has DOHC with 4 valves per cylinder and makes a claimed 128 lb-ft of torque and 122 horsepower.

Indian has unveiled the all-new liquid-cooled PowerPlus 108, a 1,768cc (108ci) V-twin that makes a claimed 128 lb-ft of torque and 122 horsepower and will be the beating heart of a new fixed-fairing bagger called the Challenger.

Rider got a chance to see and experience the PowerPlus 108 during a multi-day, hush-hush ride on the Challenger, and we’ll post a full review when the embargo lifts on Tuesday, October 29. For now, we can only reveal details about the new engine.

With ever-tightening emissions regulations, the era of air-cooled engines is drawing to a close. Euro 5 standards, which go into effect on January 1, 2020, further reduce limits for carbon monoxide, hydrocarbons and nitrogen oxides, and adapting air-cooled engines to meet these standards will become increasingly difficult.

Indian PowerPlus 108 V-twin
Unlike the liquid-cooled Scout engine its based on, Indian’s new PowerPlus 108 V-twin has a nod to traditionalists with small cooling fins near the tops of its cylinders.

Indian’s air-cooled Thunder Stroke 111/116 V-twin has powered all of its heavyweight baggers and tourers since it debuted for 2014. Rather than implement partial liquid cooling like Harley-Davidson did with its Twin-Cooled Milwaukee-Eight V-twin and BMW did with its R-series boxer twin, Indian decided to go all-in with liquid cooling for the PowerPlus 108. And it didn’t have to go far for inspiration. Indian’s middleweight Scout lineup is powered by a liquid-cooled, 60-degree V-twin with DOHC and 4 valves per cylinder, and the PowerPlus has the same engine configuration and 4 valves per cylinder but uses a SOHC head.

Interestingly, PowerPlus revives the name given both to an 18-horsepower 1,000cc V-twin and the motorcycle it powered, which Indian produced from 1916 to 1924. The U.S. War Department ordered 20,000 PowerPlus motorcycles for service during World War I, and the PowerPlus helped Erwin “Cannonball” Baker set several endurance records. According to motorcycle historian Tod Rafferty, when the 600cc Scout was introduced in 1920, it “was basically a downsized Powerplus.” Today’s PowerPlus, on the other hand, is basically an upsized Scout.

READ: 2019 Indian FTR 1200 S First Ride Review

Indian says the PowerPlus “was developed with a big-piston, big-torque mindset with an end game of maximum power delivery across the entire curve.” With an oversquare bore and stroke of 108.0 x 96.5mm, the PowerPlus 108’s 1,768cc displacement is 122cc smaller than that of the 1,890cc Thunder Stroke 116 found in most of Indian’s heavyweight lineup for 2020, but the PowerPlus makes more claimed torque: 128 lb-ft at 3,800 rpm versus 126 lb-ft at 2,900 rpm. The PowerPlus also revs higher, redlining at 6,500 rpm versus 5,300 rpm on the Thunder Stroke.

Dual-bore 52mm throttle bodies take big gulps of fuel and air, which is compressed at a ratio of 11.0:1. With throttle-by-wire actuation, the PowerPlus offers three riding modes with different throttle response settings. The unit crankcase has a semi-dry oil sump that holds five quarts. To reduce maintenance and improve reliability, the overhead camshafts have hydraulic chain tensioners and the valves have hydraulic lash adjusters. The 6-speed constant mesh transmission has an overdrive top gear and a cable-actuated wet assist clutch.

Indian says the “PowerPlus was tested, refined and proven by one of the industry’s most rigorous development and testing programs, accumulating over one million miles of simulated testing, including state-of-the-art dyno testing, and more than 300,000 on-road miles.” Designing and developing an entirely new engine is a major investment, and Indian clearly sees the PowerPlus as worth the effort.

Unfortunately, we are prohibited from providing any riding impressions about the PowerPlus or the Challenger or other information at this time. Check back on October 29 for the full story.

Check out Rider‘s 2020 Guide to New Street Motorcycles

6 COMMENTS

  1. It’s a new journey for another American made motorcycle industry.
    I have experienced the liquid cooling on my 1982 Honda Magna 750 . I miss that bike and the comfort,reliability and power.
    38 years later I ride Harley Davidson Ultra Classic and CVO Road Glide. Air cooled.
    I believe the move Indian PowerPlus 108 liquid cooling is a positive step.
    I can’t wait to review it at the Indian Motorcycle dealership in DePere, WI at the end of the month.

  2. Wow! I have been enjoying my V4 liquid cooled Yamaha Royal Star Venture, first my 1999, and now my 2003. I was attracted to the Roadmaster as a possible replacement for my RSV. I loved the looks and package, but all reports spoke of the excessive heat. I was disappointed when Yamaha chose to discontinue the RSV and replace it with an air cooled large V-twin. Many RSV owners felt an improved and upgraded RSV, retaining the liquid cooled engine would have been a better choice and a better investment. I’m not aware of any RSV owners who have gone to the new models.
    So, I will be watching closely this new Indian, and perhaps after my 50+ years of riding, it may be my new & last new bike.

  3. As a Victory Vision owner with 93,000 miles on her, I’m very interested in Indian’s fixed faring model.
    I want all the bells and whistles that my 2011 Vision has, including electrically adjustable windscreen, ABS, heated grips, stereo, and 5,000 mile oil changes.

  4. Interestingly, the PowerPlus name was revived by Indian Motorcycles in 2002, when they were being built in Gilroy, California. It was re-revived when Stellican restarted the brand in Kings Mountain, North Carolina, and Polaris continued that re-revival when they bought the company from Stellican, and moved production to Spirit Lake Iowa, keeping the engine and the PowerPlus name in use until the introduction of the Thunder Stroke engine in 2014

  5. If I like the frame/type bike they put this engine in I will consider it only if it has reverse. I ride with allot of guys with this feature (BMW-Goldwings) And at my age for a Heavy bike it’s a must. Currently own a 2015 BWM R1200RT but kinda miss my Street Glide

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