This service repair manual provides comprehensive coverage for the BMW R26 and R27 motorcycles produced between 1956 and 1966. These iconic models, representing BMW's commitment to engineering excellence and reliability, feature horizontally-opposed twin-cylinder engines with shaft drive. The R26, known for its 247cc OHV engine and plunger rear suspension, and the R27, distinguished by its 247cc OHC engine and Earles-type leading-link fork, offer a classic riding experience. This manual delves into the intricate details of these machines, designed for owners who value performance and longevity. This factory service repair manual offers hundreds of pages of detailed information, including step-by-step instructions, troubleshooting guidance, and factory-level technical specifications. It covers all major systems, from the fuel and electrical systems to the engine, transmission, brakes, and suspension. With hundreds of photos and illustrations, this comprehensive English-language guide empowers owners and technicians to perform maintenance, diagnostics, and repairs effectively, ensuring the continued optimal performance and longevity of their BMW R26 or R27 motorcycle.