1971 Yamaha AT1 Service and Repair Manual

Early seventies Yamaha two-strokes were serviced from shared literature, and the AT1 is one of them. The factory book is LIT-11613-14-01 and the code on this 1971 machine is AT1C.

Yamaha wrote that volume to carry the 1971 through 1973 model years, and it documents the AT2 and AT3 alongside the AT1, plus the CT1, CT1C, CT2, CT3, LT2 and LT3. These machines share enough of their design that one set of procedures serves them, with the differences called out where they occur.

The content is workshop material: engine disassembly and reassembly in order, clearances and torque figures, carburettor and ignition settings, wiring diagrams and fault-finding steps. For a bike of this age that specification data matters more than anything, because parts are often mismatched and only measurement tells you what you actually have. Confirm the AT1C code before following a procedure.