If you have to undertake maintenance tasks on your Yamaha RD 500 LC then it will always be recommended to own a Workshop Manual to keep just for personal reference if perhaps you need to know how to take out a particular component for example Clutch and install it again adequately.
Yamaha RD 500 LC Workshop Manuals will give certain diagnostic info for the car or truck so if something is faulty it will help you understand what the issue is and tips on how to resolve it. After that you can analyse if this can be done on your own or in case the job is too big you can actually make a reservation for your RD 500 LC in to a suitable repair garage.
Yamaha RD 500 LC manual