This comprehensive service repair manual is your essential guide to maintaining and repairing your 1940-1947 Harley Davidson Big Twins Knucklehead and Flathead motorcycles. It features detailed illustrations and step-by-step instructions designed to empower both novice and experienced mechanics. This manual offers a complete dis-assembly approach, enabling you to understand each component and its function. With hundreds of photos and illustrations, this manual guides you through every service and repair procedure. You'll find comprehensive coverage of all critical systems, including the engine, transmission, electrical system, chassis, and more. This manual is your trusted resource to keep your classic Harley Davidson running smoothly and reliably.

The 1940-1947 Harley Davidson Big Twins Knucklehead and Flathead motorcycles were iconic machines that epitomized the American spirit of freedom and adventure. These legendary bikes, powered by the revolutionary Knucklehead and Flathead engines, marked a significant shift in motorcycle design and performance. The Knucklehead engine, introduced in 1936 and bearing its name due to its distinctive rocker arm design, boasted an overhead valve configuration that provided significant power and efficiency. The Flathead, a side-valve engine, was a robust and reliable powerplant that had been a mainstay for Harley-Davidson since the 1920s. Both engines were renowned for their durability and ability to handle long distances and challenging terrains, making them a favorite among riders who valued reliability and performance. The Big Twins were not just about brute power; they were stylish and meticulously crafted machines. The 1940-1947 models featured a distinctive chrome-plated front end, a comfortable dual seat, and a sleek, streamlined design. These bikes were known for their effortless cruising capabilities and their ability to handle a variety of riding conditions. The Big Twins played a significant role in World War II, serving as reliable transportation for military personnel. Post-war, these motorcycles became symbols of freedom and adventure, influencing generations of riders and becoming cherished collector's items. The 1940-1947 Harley-Davidson Big Twins Knucklehead and Flathead represent a pivotal moment in motorcycle history, combining technological innovation with timeless design, and leaving an enduring legacy on the motorcycle world.