If you wish to conduct fixes on your Sachs Roadster 125 then it is always a good plan to have a Workshop Manual for personal reference in case that you need to know methods to take off a certain component for instance the Wheel and install it again accordingly.
Sachs Roadster 125 Workshop Manuals will give exact diagnostic info with regards to your vehicle so if something is broken it will help you determine what the problem is and how to make it better. After that you can evaluate if you can do this on your own or that the job is too big you can actually make a reservation for your Roadster 125 right into a decent car garage.
Sachs Roadster 125 manual