1991 Yamaha MOTO-4 Service and Repair Manual

The book numbered LIT-11616-YF-25 handles the 1989 to 1991 MOTO-4 machines, the MOTO-4 250 included. For 1991 the code is YFM250B, and that is what to check against the frame before you trust a torque figure or a clearance.

Factory manuals from this period walk through a job in the sequence a dealer technician used, including the checks that decide whether a part is reusable. Engine work, the transmission and final drive, brakes, steering and suspension, and the electrical system each get their own chapter, with exploded views for parts identification.

Fluid specifications and capacities are listed in the opening chapter alongside the maintenance intervals. The wiring diagram is the full harness rather than a simplified sketch, which is usually what an owner needs when a thirty-year-old circuit goes intermittent.