Harley Davidson Knucklehead 1940-1947 Factory Repair Manual

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The Knucklehead, produced from 1940 to 1947, represents a pivotal era in American motorcycle engineering. Available in EL (74 cu in) and FL (80 cu in) variants, these motorcycles are...

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Taper: Motorcycle

Distributeur:

UGS: 52345

Mots clés: 1940 1941 1942 1943 1944 1945 1946 1947 Engines Featured Harley Davidson Knucklehead Motorcycle

Variantes de produits

Description

The Knucklehead, produced from 1940 to 1947, represents a pivotal era in American motorcycle engineering. Available in EL (74 cu in) and FL (80 cu in) variants, these motorcycles are powered by a robust Overhead Valve V-Twin engine, a design that earned the model its distinctive nickname from the shape of its rocker box covers. The Knucklehead succeeded the Flathead series, marking a significant advancement in performance and styling for a brand with a heritage dating back to 1903. These iconic machines are celebrated for their powerful engines and enduring legacy, making them highly sought after by collectors and enthusiasts. This Factory Service Repair Manual is an indispensable guide for owners and technicians working on Knucklehead motorcycles from 1940-1947. It provides comprehensive, factory-level detail across all major systems, including general information, maintenance, chassis, fuel, cooling, engine, clutch, transmission, drive systems, wheels, brakes, suspension, steering, frame, and electrical components, complete with wiring diagrams. The manual offers detailed step-by-step repair procedures, diagnostic troubleshooting guides, and tuning and adjustment instructions for common issues such as oil leaks, carburetor tuning, and ignition system maintenance, ensuring the longevity and optimal performance of these classic V-Twins.

🏷️ Basic Information

Identification

Make:

Harley-Davidson

Model:

Knucklehead

Model Variant:

EL (74 cu in OHV V-Twin), FL (80 cu in OHV V-Twin)

Production Years Covered:

1940, 1941, 1942, 1943, 1944, 1945, 1946, 1947

Engine Type:

Overhead Valve (OHV) V-Twin

👋 Introduction

Market Position

Market Position:

Essential resource for owners and restorers of vintage Harley-Davidson Knucklehead motorcycles. Targets enthusiasts seeking authentic factory repair information.

Competitive Analysis

Competitive Analysis:

This is an official factory service manual, providing direct factory specifications and procedures, distinguishing it from aftermarket or third-party publications. Its comprehensiveness and accuracy are key selling points.

Key Features

Key Features:

Official factory content, detailed step-by-step instructions, hundreds of pages, extensive system coverage, diagnostic troubleshooting guides, printable format, digital download for immediate access.

📋 Manual Details

Coverage Areas

Systems Covered:

General Information, Maintenance, Chassis, Fuel System, Cooling System, Engine, Clutch, Engine Lubrication System, Engine Removal/Installation, Drive, Transmission, Wheels/Tires, Final Drive, Brakes, Suspension, Steering, Frame, Electrical System, Wiring Diagrams

Page Count

Page Count:

Hundreds of pages (specific count not provided, but indicated as extensive)

Manual Type

Manual Type:

Factory Service Repair Manual

Language

Language:

English

Format

Format:

PDF Download

📖 Manual Coverage

Systems Covered

Engine Systems:

Engine assembly, disassembly, lubrication, cooling, fuel delivery, ignition, troubleshooting engine faults, tuning

Drivetrain Systems:

Clutch operation and repair, transmission servicing, primary drive, final drive, gear shifting mechanisms

Chassis Systems:

Frame inspection and repair, suspension (forks, rear shocks), steering head bearings, wheel and tire servicing, brake system overhaul and adjustments

Electrical Systems:

Wiring diagrams, lighting systems, ignition system components, generator/charging system, troubleshooting electrical faults

Procedures Included

Maintenance Procedures:

Routine servicing, lubrication schedules, fluid level checks, filter replacement, brake adjustments, spark plug service, battery maintenance

Repair Procedures:

Step-by-step instructions for engine rebuilds, transmission overhauls, carburetor servicing, electrical component replacement, brake system repairs, suspension overhauls, frame straightening, and more

Diagnostic Procedures:

Troubleshooting guides for common engine, transmission, electrical, and chassis problems, fault symptom diagnosis, component testing methods

Tuning And Adjustment:

Carburetor adjustment, ignition timing, valve clearance adjustment, clutch and brake lever adjustments, suspension tuning

Technical Depth

Depth Of Coverage:

Comprehensive factory-level detail, suitable for professional technicians and experienced DIY mechanics. Covers everything from basic maintenance to complete engine and transmission rebuilds.

📊 Manual Specifications

File Format

File Format:

Print Quality

Print Quality:

High resolution, fully printable. Users can print individual pages, chapters, or the entire manual.

Binding Type

Binding Type:

Digital download (printable). No physical binding.

Paper Type

Paper Type:

Not applicable (digital product). User can choose paper type for printing.

⚙️ Engine Specifications

Primary Engine

Engine Configuration:

45-degree OHV V-Twin

Engine Displacement El:

74 cubic inches (1213 cc)

Engine Displacement Fl:

80 cubic inches (1309 cc)

Bore El:

3-7/16 inches

Stroke El:

4-5/16 inches

Bore Fl:

3-9/16 inches

Stroke Fl:

4-5/16 inches

Performance

Horsepower El:

Approximately 30-35 hp (varies by year and tuning)

Horsepower Fl:

Approximately 35-40 hp (varies by year and tuning)

Fuel System

Carburetor Type:

Linkert M-series (e.g., M51, M61, M74) depending on year and displacement

Fuel Delivery:

Gravity feed from tank, typically with a vacuum-operated fuel valve.

🔧 Transmission

Standard

Transmission Type:

4-speed, constant mesh, foot clutch, hand shift (left side) or hand clutch, foot shift (right side) depending on year.

Optional

Optional Transmissions:

None offered from factory during this period.

Features

Clutch Type:

Wet multi-plate clutch, operated by foot pedal or hand lever.

📐 Dimensions

Exterior

Wheelbase Approx:

57.5 inches (1460 mm)

Weights

Dry Weight Approx El:

525 lbs (238 kg)

Dry Weight Approx Fl:

550 lbs (249 kg)

🛡️ Safety Features

Ratings

Safety Ratings:

N/A (Vehicle Safety Standards as we know them today were not prevalent for this era of motorcycle. Focus is on mechanical integrity and safe operation principles.)

Active Features

Active Safety Features:

Mechanical drum brakes (front and rear), stable frame geometry, rider control through clutch and shifter operation.

Passive Features

Passive Safety Features:

Robust frame construction, durable components. Focus on rider awareness and control.

💡 Technology Features

Infotainment

Infotainment Features:

N/A. This era of motorcycle does not feature infotainment systems. Focus is on mechanical and electrical functionality.

Driver Assistance

Driver Assistance Features:

N/A. No electronic driver assistance features.

Connectivity

Connectivity Features:

N/A. No electronic connectivity features.

🔧 Maintenance

Service Intervals

Oil Change Interval:

Recommended every 1,000 miles or seasonally. Specific oil type and capacity will be detailed in the manual.

Spark Plug Service:

Check and gap spark plugs every 1,000-2,000 miles. Manual will provide specific plug types and gap specifications.

Chain Adjustment:

Primary chain and rear chain require periodic inspection and adjustment to prevent wear and ensure smooth operation. Specific procedures and slack tolerances will be outlined.

Fluid Specifications

Engine Oil Type:

The manual will specify the correct viscosity grade (e.g., SAE 50 or SAE 60 for older air-cooled engines) and type (e.g., mineral oil, specific Harley-Davidson formulations or equivalents).

Transmission Fluid Type:

The manual will detail the recommended gear oil for the transmission and primary drive. Often a specific weight gear oil was used.

Brake Fluid Type:

Likely DOT 3 or DOT 4 hydraulic fluid for the brake systems, though the manual will confirm specific requirements if applicable.

Known Issues

Known Issues:

Common issues for Knuckleheads can include oil leaks (typical for vintage air-cooled V-twins), carburetor tuning challenges, clutch adjustment issues, and potential wear on valve train components over time. The manual provides solutions for these.

Ignition System:

Early ignition systems (points and condenser) require periodic maintenance. The manual will guide through timing adjustments and component checks.

📚 Vehicle History

Brand Heritage

Brand Heritage:

Harley-Davidson, founded in 1903, has a long-standing legacy in American motorcycle manufacturing, known for its powerful V-twin engines and iconic styling.

Model Evolution

Model Evolution:

The Knucklehead (officially the E and EL for 61 cubic inch, F and FL for 74 cubic inch models) succeeded the Flathead series and was the first Harley-Davidson Big Twin to feature overhead valves, earning its nickname from the shape of its rocker box covers. It was a significant step forward in performance and design.

Production

Production Period:

1936-1947

Wartime Production:

Production during WWII was significantly scaled back for civilian markets, with many bikes repurposed for military use or production focusing on military needs. This manual covers the civilian production years including the transition through the war.

🏆 Awards & Recognition

Recognitions

Recognitions:

The Harley-Davidson Knucklehead is widely considered a classic and highly desirable motorcycle among collectors and enthusiasts, often winning awards in vintage motorcycle shows and competitions for its historical significance and design.