If you wish to do repairs for your Yamaha XJ 650 then it is always a good plan to own a Workshop Manual to use as a reference in case that you want to know tips to take out a particular part such as the Brake Discs and fit it again in the correct way.
Yamaha XJ 650 Workshop Manuals will give you exact diagnostic information for your vehicle so if something is playing up it helps you work out what the issue is and how you can fix it. You will be able to analyse if you can do this on your own or if the job is too big you can still book your XJ 650 in with a decent repair garage.
Yamaha XJ 650 manual