Yamaha listed the 1981 36-volt car as G1-E2, and the shop manual for it is part number LIT-11616-G1-AE.
Seven variants and the 1979 to 1981 model years share this book. The carbureted cars are in there as well, which means chassis procedures are documented once for the whole early G1 family and the drivetrain chapters split where the cars genuinely differ.
The electrical sections cover the motor, control circuit and charging system with the readings Yamaha expected at each point, backed by the complete factory wiring diagram. Mechanical sections deal with the rear axle, brakes, steering and front suspension, each with removal sequence, service limits and torque values. A maintenance schedule at the front states the inspection intervals. It is factory text throughout, which is why the numbers hold up.
