2016-2017 Harley-Davidson FLSS Softail Slim S: Twin Cam 110B Factory Bobber

The Harley-Davidson FLSS Softail Slim S was a short-lived but important late-Twin Cam Softail: a production Softail Slim fitted from the factory with the 110 cubic-inch counterbalanced Twin Cam 110B engine previously associated mainly with CVO machinery. Sold for the 2016 and 2017 model years, it sat at the intersection of three Harley-Davidson currents: the blacked-out factory-custom movement, the company’s nostalgia for postwar bobbers, and the final phase of the Twin Cam Softail platform before the 2018 Milwaukee-Eight redesign.

It was not a racing motorcycle, a police model, or a limited CVO. Its significance is more subtle and more relevant to modern Harley collectors: the Softail Slim S was one of the factory hot-rod Softails that put the 110B engine into a regular-production chassis, giving buyers a large-displacement, rigid-look cruiser with genuine catalog legitimacy rather than an owner-built big-bore conversion.

Best Known For: the FLSS Softail Slim S is best known as the 2016-2017 factory 110B version of the Softail Slim, combining Harley-Davidson’s late Twin Cam big-inch engine with a low, blacked-out, military-tinged bobber stance.

Quick Facts

The following table summarizes the FLSS in the form most useful to an enthusiast checking identity, specification, or model-year relevance. Harley-Davidson literature did not publish a factory horsepower figure for this model, so horsepower is deliberately omitted.

The FLSS is easy to misunderstand if approached only as a trim package. The paint and blacked-out hardware matter, but the defining element is mechanical: the 110B engine in a Softail Slim chassis.

Why the FLSS Softail Slim S Matters

The Softail Slim S deserves its own page because it was not simply a Softail Slim with darker paint. It represented Harley-Davidson’s decision to put a high-output, large-displacement Twin Cam B engine into a non-CVO Softail at the end of that engine family’s production life. That timing gives the FLSS a collector hook separate from ordinary mileage, color, or bolt-on accessories.

Within Harley-Davidson’s modern history, the 2016-2017 S-model Softails are transitional motorcycles. They were built before the 2018 Softail platform absorbed the Dyna line and moved to the Milwaukee-Eight engine, but after the Twin Cam had matured through displacement increases, hydraulic cam-chain systems, six-speed gearboxes, and broader electronic equipment. The Slim S is therefore one of the most developed factory expressions of the counterbalanced Twin Cam Softail.

Its appeal is also visual. Harley did not dress the FLSS as a touring cruiser or a chromed boulevard ornament. With black finishes, wire wheels, a low solo-seat profile, floorboards, and available Olive Gold Denim military-influenced paint, it looked deliberately stripped, heavy, and functional. It was a catalog motorcycle with the posture of a privateer bob-job, which is precisely why original examples are worth separating from ordinary modified Softails.

Historical Context and Development Background

By the middle of the 2010s, Harley-Davidson’s Big Twin line was being pulled in several directions. Touring motorcycles had become increasingly refined, CVO models showcased displacement and finish, and the factory-custom segment had proved that many buyers wanted motorcycles that looked modified before leaving the dealer. The Softail line, with its hidden rear suspension and hardtail silhouette, remained the natural platform for nostalgia-driven cruisers.

The standard Softail Slim, introduced earlier in the decade, already had the right visual language: low seat, abbreviated fenders, laced wheels, floorboards, and a simplified postwar stance. The S version took that premise and gave it the largest regular-production Softail engine of the moment. The Twin Cam 110B was not merely a bigger number on the air cleaner; in Softail form it required the counterbalanced “B” configuration because the engine was rigid-mounted in the chassis.

The competitor landscape was less about Japanese cruisers than about Harley-Davidson’s own showroom. A buyer cross-shopping a Slim S could be looking at a standard FLS Softail Slim, a Fat Boy S, a Breakout, or a used CVO. The FLSS mattered because it offered the 110B engine without the bulk and visual mass of the Fat Boy S, and without the full CVO treatment. It was leaner, visually older, and more focused.

Engine and Drivetrain

The FLSS used Harley-Davidson’s Twin Cam 110B, an air-cooled, 45-degree pushrod V-twin with two valves per cylinder and internal counterbalancers for the rigid-mounted Softail chassis. Displacement was 110 cubic inches, or 1801 cc, achieved through a 4.0-inch bore and 4.374-inch stroke. Factory literature listed peak torque at 109 lb-ft at 3500 rpm under the J1349 test method; Harley-Davidson did not publish a factory horsepower figure for this model.

Fueling was electronic sequential port fuel injection, and ignition was electronically controlled. Like other modern Big Twins of its period, the engine used hydraulic lifters and dry-sump lubrication. The six-speed Cruise Drive gearbox and belt final drive made the FLSS a relaxed, low-rpm road motorcycle rather than a high-revving performance machine.

The table below is restricted to documented mechanical specifications and avoids dyno figures, aftermarket claims, or owner-estimated horsepower numbers.

The important mechanical distinction is the “B” suffix. Softail Twin Cams used counterbalanced engines because the power unit was rigidly mounted, unlike rubber-mounted Dyna and Touring models. That gave the Slim S a more solid mechanical connection to the chassis than a rubber-mounted Big Twin while keeping vibration within acceptable road-bike limits.

Chassis, Suspension, and Braking

The Softail chassis is central to the FLSS identity. It presents the visual line of a rigid rear frame, but the rear suspension is hidden beneath the motorcycle. This was the Softail formula from the Evolution era onward, and by the Twin Cam 110B years it was a mature architecture: low, heavy, stable, and deliberately traditional in appearance.

The Slim S used a telescopic front fork, 16-inch wire-spoke wheels, full fenders, floorboards, and a solo saddle. Its stance is very different from a long, wide-tire custom such as the Breakout. The FLSS carries its weight low, visually compresses the rider into the motorcycle, and uses the fat 16-inch wheel vocabulary associated with postwar Harley big twins rather than the stretched look of later custom cruisers.

On the road, the chassis priorities are stability, appearance, and low-speed accessibility rather than sporting agility. That is not a criticism; it is the design brief. The Softail Slim S was built to deliver big torque and visual compression, not to imitate a Dyna or Roadster.

Riding Experience and Mechanical Character

The FLSS starts like a modern injected Harley, not an old kickstart bobber. The ritual is key-on, fuel pump prime, thumb the starter, and the large Twin Cam settles into a heavy, slow-pulsing idle through its dual exhaust. The counterbalanced engine takes the hard edge out of the rigid-mount arrangement, but it does not remove the character; the rider still feels a large crankshaft and long-stroke engine working below the tank.

The torque delivery is the reason the motorcycle exists. The 110B does not need to be revved hard to feel forceful, and the six-speed gearbox lets the rider keep the engine in the broad middle of its range. Throttle response is modern and metered compared with carbureted Big Twins, but the motorcycle retains the mass, flywheel feel, and mechanical tempo expected of a large air-cooled Harley.

The clutch and gearbox are substantial rather than delicate. Shifts through the Cruise Drive transmission have the familiar Big Twin weight, and the belt final drive keeps the machine clean and quiet compared with a chain final drive. Floorboards, a low saddle, and the wide handlebar place the rider in a relaxed but commanding position, though cornering clearance and braking performance remain cruiser-realistic rather than sporting.

Compared with the roads that inspired its styling, the FLSS is far more competent than a true postwar bob-job. It has electric starting, fuel injection, disc brakes, ABS equipment, and modern tires. Yet its sensory appeal is deliberately old-fashioned: low seat, visible cylinders, laced wheels, black hardware, and the sense that the motorcycle is built around the engine rather than around aerodynamics or electronics.

Identification and Originality

Correct identification begins with the FLSS model code and the 2016-2017 model-year range. The easiest mistake is to confuse a standard FLS Softail Slim with a Softail Slim S that has been modified, or to assume any Slim with a 110-style air-cleaner insert is an FLSS. Documentation, VIN information, factory labels, and original sales paperwork matter more than cosmetic cues alone.

Original FLSS equipment centered on the Twin Cam 110B engine, blacked-out finishes, laced wheels, solo saddle, floorboards, and Softail Slim bodywork. Paint is part of the story: Vivid Black and Olive Gold Denim are the colors most closely associated with the model, with the Olive Gold Denim version often remembered for its military-influenced tank graphic. That military flavor was stylistic rather than functional; the FLSS was not a military motorcycle.

Common originality concerns include aftermarket exhaust systems, high-flow air cleaners, fuel tuners, altered handlebars, two-up seat conversions, detachable windshields, luggage racks, and non-stock wheels. Many of these changes are reversible, but factory exhaust, intake parts, correct black trim, and original paint can be costly or tedious to source in excellent condition. For collectors, a carefully preserved FLSS with its stock parts retained is materially different from a heavily personalized example with only the model code left to prove its identity.

Engine and frame-number concerns are those of a modern Harley rather than a prewar machine. The frame VIN, title, emissions labels, and service records should agree. Avoid unsupported decoding shortcuts: confirm the motorcycle through official documentation and factory-style identification, not hearsay about trim or accessories.

Model Code and Variant Breakdown

The FLSS sits within the Softail Slim family but is mechanically distinct from the standard FLS. The table below separates the model most relevant to this page from closely related showroom relatives that are often compared by buyers and restorers.

This distinction is important in the collector market. A correct FLSS is not merely a Slim upgraded with a big-bore kit, and it is not a CVO. Its value proposition rests on factory specification: 110B power in the restrained Slim package.

Performance and Dimensional Specifications

Harley-Davidson factory literature listed the FLSS engine torque at 109 lb-ft at 3500 rpm and the displacement at 110 cubic inches. The company did not publish a factory horsepower rating for the model, and independent dyno figures vary with exhaust, intake, calibration, break-in, and testing method. Serious buyers should treat horsepower claims as evidence of a particular motorcycle’s state of tune, not as a factory specification.

Factory listed running-order weight is approximately 712 lb, with a 5.0-gallon fuel capacity. Period road tests and owner discussions may quote different measured weights depending on fuel load and accessories. Top speed, quarter-mile performance, and 0-60 mph figures are not consistently useful collector references for the FLSS because the model’s identity is defined by engine specification, chassis family, and originality rather than by standardized acceleration testing.

Compared With Related Harley-Davidson Models

FLSS Softail Slim S vs FLS Softail Slim

The standard FLS Softail Slim is the closest visual relative and the source of most identification confusion. It has the same general low bobber vocabulary, but the FLSS brings the 110B engine and S-model blacked-out execution. For riders, the difference is most obvious in midrange torque; for collectors, it is the factory model code and engine specification that matter.

FLSS Softail Slim S vs FLSTFBS Fat Boy S

The Fat Boy S shares the 110B idea but expresses it differently. The Fat Boy S is broader, visually denser, and tied to the Fat Boy’s solid-wheel identity. The Slim S is the more pared-back motorcycle, with wire wheels and a stance closer to Harley’s postwar custom memory.

FLSS Softail Slim S vs CVO 110 Softails

CVO models with 110 engines occupy a different collector lane. They typically bring special paint, higher equipment levels, and limited-production prestige. The FLSS is more restrained and arguably more coherent as a rider’s motorcycle: less ornamented, more bobber-like, and still factory-correct with the big engine.

FLSS Softail Slim S vs Milwaukee-Eight Softail Slim

The 2018 redesign changed the Softail frame, engine family, suspension behavior, and broader Harley-Davidson product strategy. A Milwaukee-Eight Softail Slim is more modern in platform terms, but it is not a Twin Cam 110B machine. For collectors focused on the last Twin Cam Softails, that distinction is decisive.

Restoration and Ownership Notes

The FLSS is modern enough that restoration usually means returning a modified motorcycle to factory specification rather than fabricating missing ancient parts. Mechanical parts support for Twin Cam-era Harleys remains strong, and specialist knowledge is widespread. The difficulty lies in finding correct original take-off parts, preserving factory finishes, and undoing unsympathetic tuning or cosmetic work.

Known ownership concerns are typical of large-displacement late Twin Cam Harleys rather than unique FLSS defects. Heat management, exhaust changes, fuel calibration, compensator condition, clutch wear, lifter condition, and cam-drive service history deserve attention. The Twin Cam 110B is stout when serviced properly, but poorly tuned intake and exhaust combinations can make these motorcycles run hot, surge, or lose the polished manners expected from a factory machine.

Spoke wheels require inspection for corrosion, loose spokes, and rim condition. ABS-equipped brakes should be serviced with correct fluid intervals and care, especially on motorcycles that have sat. Black finishes also reveal careless wrenching: rounded fasteners, scarred exhaust shields, chipped fork lowers, and mismatched hardware tell a restorer much about prior ownership.

Buyer and Restoration Inspection Points

A good FLSS inspection should be specific to the model. The question is not simply whether the motorcycle runs, but whether it remains a correct Softail Slim S rather than a modified Slim or a personalized 110B cruiser with missing factory parts.

The best examples are usually not the loudest or the most accessorized. A stock or lightly modified FLSS with complete records, original paint, and retained take-off parts is the machine most likely to satisfy both a rider and a future collector.

Collector and Market Relevance

The FLSS has several ingredients collectors tend to notice: short production span, distinctive model code, large factory engine, final-generation Twin Cam Softail identity, and a visual specification not shared by every Softail on the showroom floor. Exact production numbers are not consistently documented in public factory sources, so rarity should be discussed with care. What can be stated is that the model was sold only for 2016 and 2017, making it a brief chapter in the Softail Slim story.

Desirability is strongest when the motorcycle remains visibly and mechanically close to factory form. The Olive Gold Denim version attracts particular attention because it reinforces the military-influenced bobber image, but condition and originality still matter more than color alone. Vivid Black examples can be equally compelling when unmolested, especially because black finish quality and correct hardware are easy places for neglect to show.

The FLSS also benefits from being part of the last Twin Cam Softail moment. As later Milwaukee-Eight Softails became the modern standard, the 110B S-models took on clearer identity as end-of-line machines. They are not antique motorcycles, but they already occupy the kind of collector category that rewards specification literacy.

Cultural Relevance

The Softail Slim S belongs to Harley-Davidson’s long-running conversation with bobber culture. It did not copy a single historical Harley model, and it was not a reproduction of a military WLA or a Panhead custom. Instead, it borrowed the vocabulary enthusiasts recognize: fat 16-inch wheels, shortened visual mass, solo seat, floorboards, low fenders, subdued paint, and a large exposed V-twin as the center of the composition.

Its cultural role was commercial rather than military or racing-based. Harley-Davidson understood that many riders wanted a motorcycle that looked as if it had already passed through a good independent shop, but with factory warranty, fuel injection, ABS, and modern service support. The FLSS is one of the better examples of that strategy because the styling was backed by a meaningful engine upgrade.

In club and custom circles, the Slim S has often been treated as a strong starting point rather than a blank canvas. That is both a virtue and a problem for collectors. Many have been personalized with pipes, seats, bars, detachable screens, and performance calibrations. The fewer of those changes a surviving motorcycle carries, the more clearly it communicates what Harley-Davidson was trying to do in 2016.

FAQs

What years was the Harley-Davidson FLSS Softail Slim S produced?

The FLSS Softail Slim S was produced for the 2016 and 2017 model years. It disappeared with the end of the Twin Cam Softail generation and the arrival of the redesigned Milwaukee-Eight Softail platform.

What engine is in the 2016-2017 Softail Slim S?

The FLSS uses the Twin Cam 110B, an air-cooled, counterbalanced, 45-degree OHV V-twin displacing 110 cubic inches, or 1801 cc. The “B” version is the counterbalanced Twin Cam used in rigid-mounted Softail applications.

How is a Softail Slim S different from a standard Softail Slim?

The key difference is the factory Twin Cam 110B engine. The standard FLS Softail Slim used the smaller Twin Cam 103B in later Twin Cam years, while the FLSS received the 110B engine and S-model blacked-out styling.

Did Harley-Davidson publish horsepower for the FLSS Softail Slim S?

Harley-Davidson did not publish a factory horsepower rating for the FLSS. Factory literature listed torque at 109 lb-ft at 3500 rpm, but horsepower figures commonly seen online are usually independent dyno results or aftermarket estimates.

Is the Olive Gold Denim Softail Slim S a military motorcycle?

No. The Olive Gold Denim finish and tank graphic gave the motorcycle a military-influenced appearance, but the FLSS was a civilian production Softail. It should not be confused with an actual military Harley-Davidson.

What should buyers check first on a used FLSS?

Start with documentation proving the motorcycle is an FLSS, then check whether the original exhaust, intake, paint, wheels, and trim are intact. After that, review service history for the 110B engine, clutch, compensator, brakes, and any tuning changes.

Is the Softail Slim S collectible?

It has clear collector relevance because it was a two-year, 110B-powered Softail Slim from the final Twin Cam Softail period. The most desirable examples are original, documented, correctly finished, and not heavily modified.

Collector Takeaway

The 2016-2017 Harley-Davidson FLSS Softail Slim S matters because it captured a very specific final moment: the mature Twin Cam Softail, fitted with the big 110B engine, dressed as a factory bobber rather than a touring flagship or CVO showpiece. It is not rare in the prewar sense, and it is not mechanically exotic, but it is historically well placed and easy to define—two qualities that serious Harley collectors tend to respect over time.

The best FLSS is not the one with the loudest pipes or the longest accessory list. It is the one that still looks and feels like Harley-Davidson’s own late-Twin Cam hot rod: black, low, heavy with torque, correctly documented, and unmistakably a Softail Slim S rather than a modified standard Slim. That clarity is the motorcycle’s lasting strength.