1979 Yamaha DT250 Service and Repair Manual

For 1979 the DT250 got its own book. LIT-11616-01-25 covers that year alone, with the model code DT250F, and it does not carry other models the way the earlier combined volume did.

That makes fitment simple: confirm DT250F and the whole manual is about your machine.

The engine chapters work through removal, disassembly, inspection and reassembly in factory order, with the service limits used to judge a bore, piston, bearing or shaft. Torque specifications are listed. Carburation and ignition timing are given as factory settings rather than as recommendations. Chassis sections take in suspension, brakes, wheels and controls, and the electrical chapter includes the wiring diagram together with the test values for the components on it.

A symptom-based troubleshooting section rounds it off, useful on a bike whose last real service may have been decades ago.