Motorcycles | 25 July 20175 of the Most Innovative Indian Motorcycles Share article facebook twitter google pinterest In the early years of the 20th century, Indian motorcycles dominated the world’s racetracks, earning the brand a worldwide reputation for quality, performance, reliability, and technical innovation. Though the brand disappeared for several decades, it has come back with a roar since being purchased by Polaris Industries in 2011. Over the years, the iconic manufacturer has seen many ground-breaking models. Here’s a closer look at a handful of innovative Indians from the new book Indian Motorcycle(R): America’s First Motorcycle Company(tm). When introduced in late 1901, the Indian “motocycle” was one of the first reliable internal-combustion vehicles sold to the general public. The engine of this new machine featured an inlet-over-exhaust valve train. Sometimes called an “F-head” or “pocket-valve,” this system had an overhead inlet valve above a side-valve exhaust port, both set in a combustion chamber off to the side of the piston bore. In this Indian’s design, the intake valve resided in a removable dome. The spark plug screwed into this chamber. The intake valve was operated by piston-generated vacuum pressure, but the upward-facing exhaust valve underneath was driven by a cam and a pushrod. The cam acted directly on the pushrod in the earliest engines, with no provision for lifters between the two. The F-head was the system most commonly used at the time because moving the inlet and exhaust ports away from the piston created much less heat than a combustion-chamber design with ports located directly above the piston. This heat would melt the primitive metals used to build the exhaust valves then in use. The cool fuel-air charge that the carburetor fed into the combustion-chamber pocket off to the side of the piston also contributed to the improved cooling of the inlet-over-exhaust design. Indian attempted to market smaller-displacement motorcycles like the Featherweight and Model O by portraying them as economical and non-intimidating, but Indian engineer and racer Charles B. Franklin had a different plan: design a motorcycle from the ground up that capitalized on the performance advantages offered by a lighter, more agile motorcycle. The resulting Scout, introduced for the 1920 model year, was arguably the world’s first mass-market motorcycle aimed at a sporting audience. For a motorcycle to be nimble, it has to be compact. To make the new Scout as compact as possible, Franklin utilized a semi-unit-construction technique in which the gearbox was bolted directly to the engine, connected by primary gears rather than a primary chain drive, as used on the Powerplus (and on rival Harley-Davidson motorcycles). This stiff and tidy packaging made the new Scout one of the finest handling motorcycles ever made up until that point, allowing the rider to utilize all the power generated by the 36-cubic-inch (596-cubic-centimeter) side-valve V-twin engine. Franklin stuck with the side-valve design rather than developing an overhead-valve system as used on some pure racing machines of the day because the gasoline used at the time burned too fast to take advantage of on overhead-valve system. Flatheads were simply the fastest engines available during that era. Unlike the Powerplus engine, which featured just one camshaft to operate all four valves, the new Scout engine featured a pair of camshafts, allowing much more versatility in valve timing and overlap and duration of valve opening. This enabled Franklin to extract more power from the engine. The Scout motor produced only 11 horsepower, compared to the 16 horsepower generated by the Powerplus, but the Scout had a wet weight of just 340 pounds, meaning it could get up and move. The 37-cubic-inch Scout could attain speeds of 60 miles per hour. When Indian developed the 1928 Scout chassis to match the sophistication of its 45-cubic-inch engine, the company created one of the most iconic motorcycles of all time: the Series 101 Scout. The 101 Scout ran with the Scout 45’s phenomenally overachieving engine mounted in a frame redesigned to be longer and more stable, and with more modern styling in the bargain. The new frame allowed the motor to be mounted farther forward, placing more weight on the front wheel and improving the Scout’s already-stellar handling. The state-of-the-art engine and sublime roadability proved a winning combination: Indian won every national championship race in 1928, setting many dirt- and board-track records in the process. The 101 Scout was as strong a competitor on showroom floors as its racing cousin was on American racetracks. Indian had another winner on its hands. The 1934 Sport Scout, with its compact frame, made a terrific racing bike. The Sport Scout’s main break with tradition was that, like the Scout Pony and Motoplane, it utilized Indian’s Keystone frame, which used the engine as a stressed member. Without frame members under the engine, the new Sport Scout weighed even less than the beloved 101—385 pounds versus the 101 Scout’s 399 pounds, and a porky 427 pounds for the 203 Scout. While the weight savings alone provided handling advantages for the new Sport Scout, light weight wasn’t the only reason for the new model’s improved handling. The Sport Scout proved even more effective on the track than the fabled 101 Scout. The Sport Scout shaved 14 pounds from the 101, but even more advantageous was the increased ground clearance afforded by the absence of down tubes in the Sport Scout’s frame design. This gave the bike greater lean angle in the corners and thus more capability to carry higher cornering speeds, a critical factor in racing success. The new Sport Scout also abandoned the leaf-spring front fork that had been an Indian fixture since 1910. The leaf-spring unit was stiffer, making it more secure in racing applications than the girder fork that replaced it on the Sport Scout. However, the girder fork was more compliant in road use. By contrast, the short frame used on the Motoplane—the Sport Scout frame was basically a beefed-up version of the Motoplane’s—was much less stable than the frame used on the 101 Scout. This was an advantage on the track, where nimble handling was more useful than stability, but on the street it gave the Sport Scout choppy, unsettled handling. Overall, the Sport Scout seemed to have been designed with an eye on racing success more than on street use For 2015, Indian resurrected one of the most iconic models in its history: the Scout. About the 2015 Indian Scout’s impressive engine, Cycle World editor-in-chief Mark Hoyer wrote, “What a nice surprise to find liquid-cooling and Ducati-worthy intake and exhaust ports on this all-new 60-degree V-twin. Most intriguing is the 86 horses [magazines measure horsepower at the rear wheel; manufacturers measure at the crankshaft] it makes on the dyno. That’s conservative for 1,133cc, which promises a bright future. When I said to Kevin Cameron I thought there was an easy 140 hp in this power plant, he upped the ante quite a bit. How about a Sport Scout with similar styling and a standard-style riding position?” Rather than give the liquid-cooled engine fake cooling fins, as is done by some other cruiser manufacturers, Indian chose to highlight the natural shape of the liquid-cooled engine by polishing the aluminum of the exposed structural ribbing and other highlights. The result is an engine that appears both modern and traditional. As with virtually all other modern motorcycles, the Indian Scout’s transmission held six gears. The belt final drive might seem more of a nod to the cruiser market than the sport bike market, but anyone who has any experience with belt drives versus chain drives will grasp the wisdom of that decision. A chain-and-sprocket final-drive system has one advantage over a belt-and-pulley system: the ability to alter the final-drive ratio to an almost infinite degree in a fairly short time. But this is really only a practical advantage on a racetrack; in functional use on public roads, the advantages in maintenance and upkeep offered by a belt drive far outweigh any theoretical advantages offered by a chain drive on the track. The rear suspension received a clever design touch. The extreme rake of the rear shocks mimics the hard-tail lines of the original Scout models while still providing the degree of suspension travel needed for a ride that is acceptable to twenty-first century motorcyclists. This also allowed Indian’s designers to give the bike the lowest seat height of any bike in its class. Describing the bike’s seating arrangement, which places the seat a mere 26.5 inches above the pavement, Cycle World magazine’s Peter Jones wrote, “The seat is so low that swinging a leg over it is no different than stepping over a crack in a root-heaved sidewalk.” Like the Indian Chief models, the Indian Scout featured a lightweight multi-piece aluminum frame. The most innovative part of the frame involved the casting used to incorporate the radiator for the liquid-cooled engine. The front downtubes were a one-piece casting that incorporated the steering head and also served as the radiator shrouds. The aluminum was cast in a way that preserved surface imperfections in the frame. According to Brew, this was done on purpose. “I liked the way the raw casting looked,” he explained. “No two pieces are exactly the same, but that gives the bike character.” Without doubt, the finished product has character aplenty. It’s ruggedly handsome and refined at the same time. The result is striking. Like the Chief models and the original Sport Scout, the engine is used as a stressed member of the frame—what Indian originally called the “Keystone frame.” The Keystone was revolutionary when Indian introduced it; today, it is an expected feature on any motorcycle with sporting aspirations, but still relatively rare on cruisers. Buy From an Online Retailer Indian Motorcycle(R): America’s First Motorcycle Company(tm) tells the complete story of Indian, America’s first mass-produced motorcycle maker, from its start as a bicycle manufacturer to the purchase of the brand by Polaris Industries in 2011 and the subsequent new Indian motorcycles. In the early years of the 20th century, Indian dominated the world’s racetracks, earning the brand a worldwide reputation for quality, performance, reliability, and technical innovation, but the once-mighty company fell on hard times and in 1953 was forced to file bankruptcy. The Indian brand never quite died, though, thanks in large part to fanatically devoted enthusiasts, who tried to resurrect it for over half a century. Finally Polaris, maker of the highly regarded Victory(R) brand of motorcycles, purchased the brand and released the Chief(R) and Scout(R), models that once again restored Indian to its rightful place in the motorcycle pantheon. Share article facebook twitter google pinterest If you have any comments on this article please contact us or get in touch via social media.