If you wish to accomplish fixes for your Sachs Bee 125 then it is usually recommended to own a Workshop Manual to use as personal reference just in case you want to know simple methods to remove a particular component for example, the Wheel and match it again perfectly.
Sachs Bee 125 Workshop Manuals are able to offer targeted diagnostic details on your vehicle so if something is faulty it will help you figure out what the issue is and tips on how to fix it. You will be able to evaluate if this can be done on your own or if the job is too big you can actually make a reservation for your Bee 125 in to a trusted friendly mechanic.
Sachs Bee 125 manual