1981 Yamaha Yamahopper Service and Repair Manual

Yamaha kept the Yamahopper in one service book for its 1979 through 1981 run, and LIT-11616-01-31 is that book. The 1981 machine is coded QT50H.

Restoring one of these is mostly a matter of knowing what the factory intended, and that is precisely what the manual supplies: the maintenance schedule as written, engine disassembly and reassembly in sequence, carburetor and ignition settings, chassis and brake procedures, and the wiring laid out clearly enough to trace on a bench.

Torque figures, clearances and service limits are given as original specifications. Verify QT50H against your paperwork first — the three years are close but not identical, and the manual distinguishes between them where it counts. After that, the numbers inside are the ones to hold the machine to.