To make it easier for you to choose the right manual, we have compiled various information for you below.

The following models are encompassed by this manual: Knucklehead-Flathead / Harley-Davidson Motor Company™

• 1940 Harley-Davidson Knucklehead EL
• 1941 Harley-Davidson Knucklehead FL
• 1942 Harley-Davidson Flathead U
• 1943 Harley-Davidson Flathead UL
• 1944 Harley-Davidson Knucklehead EL
• 1945 Harley-Davidson Flathead UL
• 1946 Harley-Davidson Knucklehead EL
• 1947 Harley-Davidson Knucklehead FL
  The serial numbers for the 1940-1947 Harley Davidson Knucklehead-Flathead can be found on the engine case, near the oil pump.
  Production/model years: 1940, 1941, 1942, 1943, 1944, 1945, 1946, 1947

Manual Language: English
Delivery: Download link will appear on the checkout page after your payment is complete.

More information: Get your 1940-1947 Harley-Davidson™ Knucklehead-Flathead manual here for instant download

Table of Contents

• Introduction
• Specifications
• Maintenance
• Troubleshooting
• Repair Procedures
• Wiring Diagrams
• And More

Please note that the following table of contents is a partial overview and does not cover all the sections and topics included in the manual. It provides a glimpse of the manual's content.

The 1940-1947 Harley-Davidson™ Knucklehead-Flathead manual is essential for mechanics, technicians, and owners as it provides detailed information and instructions for maintenance, troubleshooting, and repair procedures. It offers valuable insights into the specifications and wiring diagrams, making it an indispensable resource for anyone working with this iconic motorcycle model.

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Click the download button and instantly download this manual.# Maintenance Intervals and General Maintenance Tips

• Change engine oil every 1,000 miles or annually.
• Regularly check and adjust the chain tension.
• Inspect the spark plugs and replace them as necessary.
• Lubricate control cables and pivot points regularly.
• Check tire pressure and tread wear before each ride.
• Clean and adjust the carburetor periodically.
• Inspect brake pads and adjust the brake system as needed.
• Store the motorcycle in a dry, cool place to prevent rust and deterioration.

Common Issues and Solutions

• Issue: Oil leaks - Solution: Regularly check and replace gaskets and seals.
• Issue: Hard starting - Solution: Maintain the battery and clean carburetor.
• Issue: Irregular idling - Solution: Adjust the carburetor and check ignition timing.
• Issue: Clutch slipping - Solution: Adjust or replace the clutch discs.
• Issue: Overheating - Solution: Ensure proper oil levels and clean the cooling fins.

Five Tips for Effective Maintenance

1. Use only high-quality engine oil suitable for vintage motorcycles.
2. Regularly clean and polish the motorcycle to prevent corrosion.
3. Keep the battery charged and terminals clean.
4. Replace worn parts with OEM Harley-Davidson parts for authenticity.
5. Attend to any minor issues immediately to prevent them from escalating.

Popular Tuning Tips and Modifications

• Upgrade to electronic ignition for better reliability.
• Install modern carburetors for improved performance.
• Add custom exhaust systems for enhanced sound and efficiency.
• Replace the suspension with modern alternatives for better ride quality.
• Install modern braking systems for improved safety.

Compatible Accessories and Attachments

• Saddlebags and luggage racks
• Windshields and fairings
• Custom seat covers
• Engine guard bars and crash bars
• Handlebar grips and mirrors
• LED lighting upgrades
• Protective covers for storage
• Performance air filters
• Vintage-style decals and badges

Owner Reviews: Strengths and Weaknesses

• Strengths: Iconic design, robust engine, historical significance.
• Weaknesses: Requires regular maintenance, parts can be hard to find, not suited for modern high-speed travel.

Frequent Repairs and Commonly Broken Parts

1. Regular oil changes and gasket replacements
2. Chain adjustments and replacements
3. Spark plug cleaning and replacements
4. Clutch adjustments and disc replacements
5. Carburetor cleaning and tuning
6. Brake adjustments and pad replacements
7. Battery maintenance and replacements
8. Control cable lubrication and replacements
9. Tire inspections and replacements
10. Cooling fin cleaning
11. Ignition system maintenance
12. Electrical wiring inspections and repairs
13. Fuel system cleaning and maintenance
14. Suspension servicing
15. Exhaust system repairs and replacements

Access your exclusive download of the OEM Harley-Davidson Motor Company™ service manual with a single click. Following your payment, the legitimate Harley-Davidson Motor Company™ factory manual and parts catalog (PDF) will be accessible on the confirmation page, and a payment confirmation will be emailed to you immediately. §