This comprehensive factory service, repair, and workshop manual covers Harley Davidson Big Twin Knucklehead and Flathead motorcycles from 1940 to 1947. It provides detailed instructions and illustrations to guide you through every aspect of maintenance, service, diagnosis, and repair. The manual encompasses a wide array of procedures, ensuring you have the resources to handle any task with confidence. Inside this manual, you will find information on both the OHV and side valve engine models. OHV engines include the 61 cu. in. (1000 c.c) and 74 cu. in. (1200 c.c) while the side valve engine models include the 74 cu. in. (1200 c.c) and 80 cu. in. (1300 c.c) Whether you're a seasoned mechanic or a dedicated enthusiast, this manual will empower you to work on your Harley Davidson with precision and expertise. The manual covers a wide range of topics, including a comprehensive trouble chart, initial servicing procedures for new motorcycles, engine lubrication, complete engine overhaul, electrical system troubleshooting and repair, carburetor servicing, transmission maintenance, wheel and hub repair, fork, frame, and handle adjustments, and even guidance on sidecar maintenance. A detailed index makes it easy to locate the specific information you need. This manual is a valuable resource for any owner of a 1940-1947 Harley Davidson Big Twin Knucklehead or Flathead motorcycle. It provides the same level of detail and expertise found in the manuals used by Harley Davidson dealers and mechanics.

The Harley-Davidson Big Twins Knucklehead and Flathead motorcycles, produced from 1940 to 1947, represent a pivotal era in the company's history and a golden age of American motorcycling. These machines were the pinnacle of performance and engineering for their time, revolutionizing long-distance riding and setting the stage for the future of Harley-Davidson. The iconic Knucklehead, with its distinctive overhead-valve engine design, offered a significant boost in power and efficiency compared to its predecessor, the Flathead. Its innovative, exposed rocker arm design, which earned it its nickname, delivered smoother operation and reduced vibration. The Flathead, although less powerful, provided a reliable and rugged foundation for the iconic Harley-Davidson legacy. Both models featured a robust, rigid frame, providing exceptional stability and durability for the demanding conditions of the time. Beyond their mechanical prowess, these motorcycles became symbols of freedom and rebellion in a post-war America. They were favored by veterans returning from the conflict, eager to explore the open road and embrace a new chapter in their lives. The iconic styling, characterized by chrome accents, a prominent headlight, and the distinctive Harley-Davidson "bar & shield" emblem, cemented their place in popular culture. These machines were not just transportation; they were expressions of individual spirit, adventure, and the American dream. The Harley-Davidson Big Twins Knucklehead and Flathead, though long discontinued, remain cherished by enthusiasts and collectors alike, their timeless design and legendary status echoing the spirit of the era they represent.