Look for LIT-11613-06-01 when you need factory service information for a 1972 XS650. The bike is listed there under the code XS650, and the volume spans the 1971, 1972 and 1973 model years.
That grouping matters on a machine this old, since parts migrate between years in the hands of successive owners. The specification tables let you check what you have against the year you are working on rather than assuming continuity.
Inside, the book follows the factory's structure: reference data and adjustment limits, engine overhaul from the top end down through the crankcase with measurements and torque at each step, transmission and clutch, and the full chassis, including fork rebuild, wheel bearings and brake service. Carburetor setting and ignition timing are given as procedures with figures, and the electrical chapter carries test values plus the wiring diagram drawn to the harness.
