INTRODUCTION
F-HEAD SINGLE- & TWIN-CYLINDER ERA
- First F-Head Single
- Silent Gray Fellow
- F-Head 11-J/K
FLATHEAD SIDE-VALVE ERA
- W Sport Twin
- Model B-21
- VLD 74
- WLD 45
- WLA 45
- Servi-Car GA
- K 45 Model
KNUCKLEHEAD OHV ERA
- EL 61
- 74 FL
PANHEAD OHV ERA
- FL 74
- FL 74 Hydra Glide
- FLH Duo Glide
IRONHEAD & EARLY SPORTSTER
ENGINES
- XL Sportster 883
- XR750
SHOVELHEAD ERA
- FLH Electra Glide
- FX Super Glide
- FXS Low Rider
- FXB Sturgis
- FXWG Wide Glide
CONTENTS
EVOLUTION ERA
- FXST Softail
- FXSTS Softail Springer
- FLSTF Fat Boy
- XLH Sportster
- XL Sportster 1200N
TWIN CAM ERA
- FXDF Dyna Fat Bob
- FLSTC Heritage Softail Classic
- FLSTSB Softail Fat Boy Lo
- FLHTCU Electra Glide Ultra Classic
- FLHR Road King
- FLHXS Electra Street Glide
- FLSS Softail Slim
REVOLUTION ENGINES
- VRSCA V-Rod
- VRSCD Night Rod
- VRSCF Muscle
- Street Rod XG 750A MILWAUKEE-EIGHT - FXBB Street Bob - FXDR
- FLHTKSE CVO Ultra Limited REVOLUTION MAX - Pan America AUTHORS 000 000 000 000 000 000 000 000 000 000 000 000 000
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In 1906, Harley-Davidson produced its sole model in “Renault Gray”— now the standard color—with red pinstriping, and traditional “Piano Black” available as a paid option. The bike’s relative quietude— thanks to a detachable exhaust that added power when removed— earned the Harley the nickname “Silent Gray Fellow,” with “fellow” denoting dependability.
For 1906, the F-head single-cylinder engine was increased to 26.84ci (440cc) and 3.125 x 3.5in (79mm x 89mm) bore and stroke, giving a top speed of about 45mph (72km/h). The otherwise unchanged engine was still cranked by a pedal and chain, as there was no starter or gearbox, and had a flat 1.255in-wide (32mm) leather-belt final drive, plus a larger flywheel for improved hill-climbing ability. An optional hand crank was also designed into the engine and became standard in 1907.
Harley’s dependable F-head single soldiered on until 1918, with the company emphasizing that cubic inches were key to increased power. Hence, in 1909, Model 5 was boosted to 30.17ci (495cc), with 3-5/16 x 3-1/2in (78 x 89mm) bore and stroke. The year was seminal. Harley, which had previously made its own carburetor, introduced the more reliable Schebler automatic float-feed carb, plus a Bosch high-tension magneto ignition driven by four gears in the timing-gear case (battery ignition, without the gears, was still offered as an alternative). Enclosed control cables replaced rod linkages, with the right-hand spark advance and left-hand twist-grip throttle (with friction-control adjustment) on the handlebar.
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SILENT GRAY FELLOW
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WLA 45
With the United States’ entry into World War II in December 1941, the military needed a simple do-everything motorcycle that was easy to ride and repair and could handle rugged terrain and tons of abuse. Considered the workhorse of Harley’s model range, the 45ci W was the smallest bike series the company made. It was also uber-reliable. Harley-Davidson ceased production on virtually all civilian motorcycles to concentrate on making the WLA models used by the U.S. armed forces to military specifications. “W” signified 45ci flathead, “L” meant high compression, and “A” signified Army use. Harley-Davidson built some 90,000 of these bomb-proof motorcycles, including 17,823 versions of the WLS sidecar and about 30,000 WLAs shipped to the Soviet Union under America’s Lend-Lease program.
The U.S. Army specified a slightly lower compression ratio than standard WLs, permitting WLAs to run on low-octane fuel. Harley reduced compression to 4.3:1 on early models.
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KNUCKLEHEAD OHV ERA 1936-1947
Throughout the Depression years, Harley-Davidson’s skeletal engineering department was at work on an all-new motorcycle that was finally unveiled on November 25, 1935, at the first annual dealers’ convention in five years. With its swoopy, streamlined art deco styling and a 61ci (1,000cc) overhead-valve V-Twin engine that promised 100mph (161km/h) performance, the Model E was an instant sensation. The bike—the legendary “Knucklehead”— would open an exciting new chapter in the company’s history.
Nicknamed for the engine’s resemblance to a clenched fist (with rocker-cover retaining nuts as four knuckles and pushrod tubes like tendons running down the back of the hand), Harley’s first production OHV engine boasted revolutionary architecture that would be used on Harley’s big twins for the next 60 years. First were those big overhead valves and a high 6:1 compression ratio which boosted power to 38hp at 4,800rpm. The “Sixty-One” did away with Harley’s traditional twin- and four-cam systems: a single camshaft with four lobes generated less gear slop and noise. It also had an advanced four-speed constant-mesh gearbox—a Harley first—that was stronger and more durable than the sliding-gear transmissions used to date. Plus, it was also the first Harley-Davidson to employ a recirculating dry-sump oil system that constantly cycled fresh cool oil through the engine in place of the outmoded, wasteful, and messy total-loss system.
However, almost as soon as it appeared to conventioneers’ whoops of applause, dealers were told “under no circumstances should this model be ordered as a demonstrator!” Despite the time-consuming road to production, the bike was nowhere near ready for the big time. Besides valve-spring breakage, its much-heralded lubrication system was faulty to a fault! Some engine parts (especially rockers) got too little oil, resulting in excessive and rapid wear of the valves, rockers, and shafts. Other parts got too much . . . as did the road asphalt. The motor gushed slippery stuff from the top end like a Texas oil well! Harley engineers spent the next six months modifying the design. Although the 61 was finally released in June, the problems persisted. In the ensuing year, Harley modified some parts multiple times. Not until 1937 could the new (and still problematic) lubrication system be fitted to the still-extant flathead side-valves, which were also dressed up in copycat Sixty-One style.
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In 1973, the Super Glide became more performance-oriented. It switched to a smaller teardrop fuel tank from the single-cylinder Sprint, and was given stiffer springs and fore and aft disc brakes. The following year, an electric start FXE option was offered. And the Super Glide’s Shovelhead engine received ongoing tinkering. But the big change came in 1981 when all Harley’s V-Twins were upgraded to the 82ci (1,340cc) Shovelhead with 7.4:1 compression plus electronic ignition. A year later, the engine slotted into an all-new and much stiffer triangulated frame with three-point elastonomer mounts and Heim-jointed turnbuckles for the FXR Super Glide II. With new five-speed transmission, improved valve guides, new cylinders and pistons, reconditioned heads, a lightweight high-performance S&S bottom end, and a 38mm (1.3in) Keihin butterfly carb, the FXR produced 67hp at 5,800rpm, ran a quarter mile in 14.2 seconds, and had a top speed of 115mph (185km/h). Perhaps more importantly, many Harley-Davidson fanatics proclaim the low-slung and handsome “Engineers’ Bike” as the best-handling, most refined Harley machine ever produced.
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ENGINE
Type: 45-degree four-stroke V-Twin, air-cooled
Distribution: Overhead valves
Displacement: 73.63ci (1,207cc); 81.65ci (1,338cc) as of 1981
Bore x stroke: 3.44 x 3.97in (87.31 x 100.8mm);
3.50 x 4.25in (89 x 108mm) as of 1981
Compression ratio: 8:1; later 7.4:1
Power: 65hp, later 67hp
Fuel supply: Bendix carburetor ø 1.50in (38mm);
Keihin carburetor ø 1.50in (38mm) as of 1976
Ignition: 12V battery and coil; electronic as of 1981
TRANSMISSION
Transmission: 4-speed
Primary drive: Duplex chain
Secondary drive: Chain
CHASSIS
Frame: Double cradle tubular steel
Front suspension: Telescopic fork
Rear suspension: Swing arm and two shock absorbers
DIMENSIONS AND WEIGHT
Wheelbase: 62.01in (157.5cm)
Fuel tank capacity: 3.5gal (13.2L); 2.6gal (9.85L) as of 1973
Oil tank capacity: 4qts (3.8L)
Dry weight: 560lbs (254kg)
PERFORMANCE
Top speed: 110mph (177km/h)
MODELS AND VARIATIONS
FX 1200: Super Glide with kick-start 74ci engine, from 1971 to 1978
FXE 1200: Super Glide with electric starter 74ci engine, from 1974 to 1980
FXE 1340: Super Glide with 82ci engine, 1981
FXR 1340: Super Glide II with 82ci engine, from 1982 to 1984
TECHNICAL DATA
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XLH SPORTSTER
By 1985, the XLH Sportster was the only Harley motorcycle that didn’t use the Evolution engine. That year marked the end of the road for the cast-iron Ironhead engine, which for the greater part of three decades had remained essentially unchanged. In 1986, the Sportster was awarded a slightly revised frame and rigid-mounted 54ci (883cc) Evolution block—a return to the bike’s original 1957 engine size—with aluminum-alloy barrels and heads, followed months later by a 67ci (1100cc) version. The “Evo Sportster” retained chain drive, an updated four-speed transmission, and, of course, the XL’s unique unit construction with mated gearbox and engine. It used 206 completely new parts among its 426 components—29 percent parts fewer in total than the Ironhead motor.
Partly due to the need to meet strict new federal emission and noise standards (the latter satisfied by adding baffles, plus a balance tube between the twin exhaust pipes), the 883cc engine struggled to reach 50hp at the 5,200-rpm redline. Acceleration wasn’t exactly thrilling, although there was plentiful power at hand thanks to ample torque. But the all-new engine was reliable and cheap (just under $4,000 when introduced), given that Harley sold the XLH 883 as a cut-price loss-leader entry-level model to boost future sales.
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Harley’s policy of repackaging individual model components around a particular engine to create something new led, in 2006, to the unveiling of the FLHXS Electra Street Glide. In essence, this stripped-down and lowered Electra Glide was presented as a sleek, streamlined hot rod bagger. It was powered by the air-cooled Twin Cam 88 V-Twin (and the following year by a Twin Cam 96) in a vibration-isolation cradle-frame mounting. Producing 86lb/ft (116Nm) torque, it pulled like a John Deere tractor all the way to the 5,500rpm limit. With a fly-by-wire throttle, Delphi sequential port fuel injection and engine management system, computerized single-fire spark ignition, and self-adjusting hydraulic lifters for its pushrod-operated overhead valves, the Twin Cam was a revolutionary update for Harley.
Although at 165lbs (74.8kg) the Twin Cam 88 engine was heavier than the Evo, its added power enabled most models to hit three-figure top speeds with ease. The 88’s lower stroke meant a slower piston speed and, therefore, greater reliability. The two cams, having two lobes apiece, provided better alignment with other engine parts. Computer analysis to predict stress points reduced crankcase machining operations from 17 for the Evo to just three for the Twin Cam. And the silent chain-driven cam was far less costly to produce than the Evo’s gear-driven cam. However, the Twin Cam’s chain tensioner was not up to par and didn’t provide the same timing accuracy. The greatly refined Twin Cam 96, which featured more than 700 new parts, resolved the issue.
In 2014, Harley-Davidson’s four-year “Project Rushmore” produced the partial liquid-cooled Twin Cam engine. The Street Glide—already Harley’s best-selling model—was upgraded to the FLHXS (“S” for “Special”) and got the 103ci (1,690cc) airand-oil-cooled High Output Twin Cam 103 engine, with a high-flow airbox, hydraulic clutch, and upgraded camshafts that gave five percent more torque than the standard Twin Cam 103.
For 2017, the FLHX’s Twin Cam 103 was replaced by the state-of-the-art, super-smooth, eight-valve air/oil-cooled Milwaukee-Eight 107, which, being counterbalanced, tamed its predecessor’s trademark Mexican jumpingbean bounce at idle. And the newly blacked-out FLHXS got the powdercoated and massive 114cih (1,870cc) Milwaukee-Eight 114, which put out a whopping 123lb/ ft (163Nm) of torque at absurdly low revs.
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FLHXS ELECTRA STREET GLIDE
REVOLUTION ENGINES ERA
2002-PRESENT
Harley-Davidson and Porsche, the German high-performance automotive specialist, aren’t exactly a logical fusion. More yin and yang, they nonetheless made air and water mix. In 1976, during the last days of AMF ownership, Harley hired Porsche Engineering to design the never-produced water-cooled V-Twin, V-Four, and V-Six Nova engines. By the mid-1990s, Harley’s customer base was aging. The company needed a more youthful, futuristic appeal that tapped into younger riders’ desire for high performance. In 1995, therefore, it decided to build a performance cruiser based on its liquid-cooled, 60-degree V-Twin VR1000 racing engine (also developed with Porsche). The Motor Company’s own engineers were busy designing the Twin Cam. Hence, it again turned to Porsche to transform the VR1000 Superbike into a lean-and-mean street machine to compete against foreign muscle bikes, but with an emphasis on quiet and low emissions rather than all-out performance.
The Revolution engines were introduced for 2002 in an aluminum-skinned model called the V-Rod. A break from Harley’s Big Twin heritage, the combo was a masterpiece of engineering and styling. Instead of a loping traditional air-cooled 45-degree V-Twin motor, Porsche’s Weissach Development Centre (aided by a handful of Milwaukee engineers) produced a water-cooled, short-stroke, 1,131cc (69ci) engine loyal to the VR1000’s 60-degree V-angle architecture. The first water-cooled production engine in Harley-Davidson’s history, it featured four valves per cylinder, dual overhead cams instead of pushrods, and sequential port fuel injection. The high-revving, 11.3:1 compression motor had a very un-Harley linear power curve and flat torque curve (it produced a relatively low 74lbft/100.3Nm at 7,000rpm). It redlined at 9,000rpm and easily pumped out 115hp at 8,250rpm—the most powerful street engine the company had produced to date.
The Revolution employed the VR single balance shaft, low and behind the one-piece crankshaft. Together with rubber engine mounting, it virtually eliminated vibration from the smooth-running engine; only the faintest quiver could be felt through the bars. A push of the starter button had the V-Rod instantly idling at 1,500rpm, with none of the pauses and clattering drama of prior Big Twins.
No previously unknown motorcycle technology was employed. But for Harley-Davidson, the engine truly was revolutionary. Porsche’s own best practices were evident. Offset cylinders permitted a one-piece crankshaft, with automotive-style side-by-side connecting rods running on plain main bearings rather than Harley’s traditional rollers. Per most Porsche engines, the Revolution’s connecting rods, crankshaft, and pistons were forged. The four valves per cylinder head were directly actuated by double overhead camshafts (four in total), optimizing breathing and combustion, especially at high engine speeds.
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