🏷️ Basic Information

Make:

Harley-Davidson

Model:

Electra Glide

Year:

1966

👋 Introduction

Historical Context:

The 1966 Electra Glide represented the pinnacle of Harley-Davidson's touring motorcycles for the era, a substantial machine designed for long-distance comfort and performance, competing with other large-displacement motorcycles and establishing Harley-Davidson's dominance in the American cruiser market.

Competitors 1966:

Direct competitors included large-displacement British twins (Triumph Bonneville, Norton Commando) and American V-twins from other manufacturers, although Harley-Davidson occupied a unique segment with its robust construction and distinctive V-twin character.

Motorcycle Features 1966:

Characteristic Milwaukee-Eight V-twin engine (though not designated as such until much later), robust frame, ample suspension, and touring amenities typical of the Electra Glide line. This model would have featured the FLH designation, signifying the higher-performance 'Hydra-Glide' (though evolving into FLH by '65 for the electric start version, the core design elements of the Glide remained).

📋 Manual Details

Primary Coverage:

Repair and Service of 1966 Harley-Davidson Electra Glide

Estimated Pages:

Varies by specific edition, typically 300-600 pages for comprehensive service manuals of this era.

Illustrations Diagrams:

Contains numerous diagrams, exploded views, and illustrations to aid in understanding assembly and disassembly processes.

Type:

Factory Service Manual / Repair Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Engine Systems:

Engine disassembly, assembly, tuning, lubrication, cooling (air-cooled), ignition system, fuel delivery (carburetion), exhaust system.

Transmission And Drivetrain:

Clutch, primary drive, transmission (gearbox) overhaul, final drive (chain drive) maintenance, lubrication.

Chassis And Suspension:

Frame inspection and repair, front fork (leading-link or telescopic, depending on specific sub-model variant) overhaul, rear shock absorber and swingarm maintenance, steering head bearing service.

Braking System:

Front and rear brake mechanisms (likely drum brakes for this era), adjustment, lining replacement, hydraulic system (if applicable) service.

Electrical System:

Wiring diagrams, lighting circuits, charging system (generator/regulator), ignition switch, battery service, horn, starter motor, instrumentation.

Bodywork And Trim:

Fender removal and installation, fuel tank mounting, seat assembly, handlebar and control mounting, fairing (if equipped) service, cosmetic repairs.

Cooling System:

Air cooling (engine fins), with detailed procedures for inspection and cleaning to ensure optimal heat dissipation.

Lubrication System:

Oil pump operation, oil passages, oil filter (if applicable, though early models might have screen filters) and lubrication points throughout the engine and chassis.

Maintenance Procedures:

Scheduled maintenance (oil changes, filter replacements, chain lubrication), tune-ups, carburetor adjustment, ignition timing.

Repair Procedures:

Component disassembly, cleaning, inspection, part replacement, reassembly, torque specifications for critical fasteners.

Troubleshooting Diagnostics:

Systematic fault finding for common running issues, electrical problems, and mechanical failures.

Engine Rebuild:

Detailed step-by-step procedures for complete engine teardown, inspection of internal components (crankshaft, connecting rods, pistons, cylinders), honing, ring replacement, bearing installation, and reassembly with specified torque values.

Transmission Overhaul:

Complete disassembly of the 4-speed gearbox, including gear selection mechanisms, shift forks, mainshaft, and countershaft. Procedures for bearing replacement, gear inspection, and reassembly are provided.

Electrical Diagnostics:

Extensive wiring diagrams for all electrical circuits. Troubleshooting guides for common electrical faults, including generator output issues, ignition system problems, and lighting failures.

Depth:

Comprehensive, covering everything from basic adjustments and fluid changes to complete engine and transmission rebuilds, electrical system diagnostics, and frame repairs. Geared towards professional technicians but accessible to skilled amateur mechanics.

Component Tolerances:

Includes critical internal component clearances, wear limits, and out-of-round specifications for cylinders, pistons, and bearings, essential for accurate rebuilding.

Special Tools:

Lists and describes specialized tools required for specific repair or adjustment procedures, such as flywheel pullers, bearing installation tools, and timing instruments.

📊 Manual Specifications

Digital Format Details:

High-resolution PDF, typically searchable text, allowing for easy navigation and printing. Designed for clear display on digital devices.

Searchability:

Typically optimized for searchability within PDF, allowing users to quickly find specific topics, part numbers, or procedures.

Printability:

Optimized for printing, with clear diagrams, illustrations, and text that reproduces well on standard printers.

Digital Binding:

N/A (Digital PDF)

Digital Paper Emulation:

N/A (Digital PDF)

⚙️ Engine Specifications

Engine Type:

Air-cooled, 45-degree V-twin, OHV (Overhead Valve)

Engine Displacement:

74 cubic inches (1208 cc)

Bore X Stroke:

3.4375 in x 4.125 in (87.3 mm x 104.8 mm)

Compression Ratio:

Approximately 7.0:1 (varies slightly by model variant and intended fuel octane)

Horsepower:

Estimated 50-55 HP (at crankshaft, at specified RPM)

Torque:

Estimated 60-65 ft-lbs (at crankshaft, at specified RPM)

Rpm For Peak Hp:

Specific RPM for peak horsepower not readily available in generic specs but detailed in the manual, typically in the 4,500-5,500 RPM range.

Rpm For Peak Torque:

Specific RPM for peak torque not readily available in generic specs but detailed in the manual, typically in the 3,000-4,000 RPM range.

Carburetor:

Typically a Linkert M74 or M74B, or potentially a Stromberg (depending on exact production run and factory specifications). Specific jetting and settings are detailed in the manual.

Fuel Type:

Unleaded gasoline, minimum 87 octane (however, leaded fuel was common and acceptable for this era).

🔧 Transmission

Transmission Type:

4-speed manual, constant mesh, foot-shifted with hand clutch lever

Electric Start:

The 1966 model year saw the introduction or widespread availability of electric start for the Electra Glide (FLH designation), making it a significant differentiator.

Primary Drive:

Enclosed chain drive from engine to transmission, running in a wet clutch and primary oil bath.

Final Drive:

Enclosed chain drive from transmission to rear wheel.

Clutch Type:

Wet, multi-plate, diaphragm spring clutch (early models may still use coil spring).

📐 Dimensions

Length:

Approx. 90-95 inches (varies with accessories and configurations)

Wheelbase:

Approx. 60.5 inches

Dry Weight:

Approx. 625-650 lbs (varies based on accessories like saddlebags and fairing)

Gross Vehicle Weight Rating:

Not typically specified as a GVWR for motorcycles in this era, but rated for rider and passenger plus luggage.

Fuel Tank Capacity:

Approximately 4.5 gallons (including reserve)

🛡️ Safety Features

Crash Safety:

Motorcycle safety standards were significantly less regulated than automotive. Focus is on structural integrity and predictable handling. No formal crash test ratings exist in the modern sense.

Braking Control:

Mechanical drum brakes, requiring skilled operation. Brake adjustment and maintenance are critical for effective stopping.

Lighting:

Headlight, tail light, brake light, turn signals (standard on Electra Glide), and running lights. Wiring and bulb types are detailed in the manual.

Suspension:

Designed for stability and load-carrying capability, the suspension is crucial for safe handling. Manual covers tuning and maintenance.

💡 Technology Features

Audio System:

Not applicable to this model. Touring features focused on mechanical reliability and comfort, not integrated entertainment systems.

Rider Aids:

No electronic rider aids. Focus is on fundamental motorcycle control and mechanical systems.

Communication Features:

Not applicable. Communications would be external to the motorcycle.

🔧 Maintenance

Engine Oil Change:

Typically every 1,000-2,000 miles or annually. Manual will specify exact interval and inspection points.

Primary Chain Case Oil Change:

Also typically every 1,000-2,000 miles. Critical for clutch and transmission longevity.

Spark Plug Replacement:

Every 3,000-6,000 miles, or as needed based on inspection.

Chain Lubrication Adjustment:

Frequent lubrication (every 500-1000 miles) and adjustment of drive chains is crucial.

Engine Oil Type:

Viscosity grade typically 20W-50 or 50W (depending on ambient temperature). Manual will specify exact API service classification and recommended brands/types. Special motorcycle oils with ZDDP additive are often recommended for vintage engines.

Primary Chain Case Oil:

Dedicated primary oil or engine oil (e.g., 20W-50). Manual will specify exact type and capacity.

Transmission Oil:

Gear oil or specific transmission fluid. Manual will specify viscosity and GL rating.

Brake Fluid:

If hydraulic brakes are equipped, DOT 3 or DOT 4 fluid would be typical. If drum brakes are purely mechanical, fluid specifications would not apply.

Fork Oil Type Capacity:

Manual will specify appropriate fork oil viscosity (e.g., 10W or 20W) and capacity per fork leg. Often requires periodic replacement.

Common Wear Items:

Valve guides, piston rings, generator brushes, regulator, clutch plates, primary chain, wheel bearings, steering head bearings, shock absorber seals.

Electrical System Quirks:

Aging wiring insulation, faulty regulators/rectifiers (generators), and points ignition system tuning can lead to starting and charging issues.

Carburetor Issues:

Linkert carburetors require specific tuning and can be sensitive to wear. Issues include hard starting, poor idling, and fuel delivery problems.

Frame And Suspension Wear:

Worn steering head bearings, wheel bearings, and suspension bushings are common on high-mileage examples, impacting handling and ride comfort.

📚 Vehicle History

Harley Davidson Legacy:

Founded in 1903, Harley-Davidson is synonymous with American motorcycling, known for its V-twin engines, robust construction, and touring capabilities. The Electra Glide line, originating in the 1960s, became the archetypal large-displacement touring motorcycle.

Electra Glide Timeline:

The Electra Glide concept began in the early 1960s. By 1965, the FL Hydra-Glide gained electric start and a fiberglass fairing, becoming the first Electra Glide. The 1966 model solidified its position as a premium touring machine with further refinements.

Manufacturing Location:

Milwaukee, Wisconsin, USA

Production Era:

Continuous production from 1965 onwards, with significant evolution in engine, chassis, and features over the decades.

🏆 Awards & Recognition

Industry Acclaim:

While specific awards for the 1966 model aren't readily documented, the Electra Glide line consistently received praise for its touring capability and robustness, solidifying Harley-Davidson's reputation in the motorcycle industry.

Owner Satisfaction:

High owner satisfaction for its intended purpose of long-distance touring, though maintenance intensity is a factor.

Regulatory Compliance:

Manufactured to standards prevalent at the time of production. Manual assists in maintaining original specifications and compliance where possible.