The BSA M20 is a historically significant motorcycle, produced from 1937 to 1955. Renowned for its robust engineering and reliability, particularly during its extensive military service in World War II, the M20 served as a vital dispatch and reconnaissance vehicle for British and Commonwealth forces. This sturdy, single-cylinder machine, featuring a 348cc side-valve engine and a chain drive, has earned a high collector value for its classic appeal and pivotal role in history. The M20 was designed for practical, dependable operation, making it a testament to British motorcycle manufacturing of its era.

This manual serves as an essential guide for the operational guidance and maintenance of the BSA M20. Covering key areas such as engine operation, gearbox maintenance, chassis and suspension care, brake system adjustments, and basic electrical system understanding, it provides comprehensive information for routine maintenance and fundamental adjustments. The manual includes procedures for daily checks, regular servicing, and pre-ride inspections, along with specific lubrication schedules and points. It is intended to assist owners, restorers, and enthusiasts in maintaining the reliability and safe operation of their M20 motorcycles.