1975 Yamaha MX400 Service and Repair Manual

One year, one machine: Yamaha part number LIT-11625-10-00 covers the 1975 MX400, model code MX400B, and nothing else.

That narrow scope is worth something on a bike this old. The specifications were written for the MX400B as built in 1975, not revised across a later run, so a figure taken from these pages is the figure Yamaha intended for it. Fastener torques are given as values, clearances and adjustment settings as measurements, and every major assembly has a stated order for coming apart and going back together. The wiring diagrams cover the electrical circuits, and the troubleshooting sections work from a reported symptom toward the part responsible.

Check the code on your own machine before you begin. MX400B confirms that LIT-11625-10-00 is the reference written for it, and that is the number to use when identifying the correct volume.