If you choose to accomplish maintenance tasks on your Yamaha XJ 900 F then it will always be a good idea to own a Workshop Manual for a reference should you want to know how you can remove a certain component much like the Gearbox and install it again accordingly.
Yamaha XJ 900 F Workshop Manuals will give you specific diagnostic wisdom for your car so if something is wrong it will help you identify what the issue is and easy methods to fix it. You can then analyse if this can be achieved on your own or that the job is too big you can actually book your XJ 900 F right into a nearby friendly mechanic.
Yamaha XJ 900 F manual