If you have to execute maintenance for your Yamaha SZR 660 then it is usually a great idea to have a Workshop Manual for personal reference in case that you need to know the best ways to take out a certain component for example the Wheel and fit it again in the correct manner.
Yamaha SZR 660 Workshop Manuals will give certain diagnostic information for the vehicle so if something is not working it will help you figure out what the problem is and how to make it better. You will be able to decide if this can be achieved on your own or that the job is too big you can actually book your SZR 660 in to a decent repair garage.
Yamaha SZR 660 manual