If you want to do adjustments to your Yamaha YZ 85 LW then it will always be a good idea to have a Workshop Manual to use as reference in the event you want to know the right way to strip off a specific part including Brake Discs and fit it again accordingly.
Yamaha YZ 85 LW Workshop Manuals are able to offer targeted diagnostic facts for the car so if something is broken it will help you identify what the situation is and methods to repair it. You can then determine if this can be done by yourself or if ever the job is just too big you can book your YZ 85 LW into a nearby friendly mechanic.
Yamaha YZ 85 LW manual