If you have to perform fixes on your Sachs MadAss 50 then it is usually a good plan to own a Workshop Manual to keep just for personal reference in the event you need to know easy methods to remove a particular part like the Drive Shaft and match it again perfectly.
Sachs MadAss 50 Workshop Manuals will provide you with special diagnostic guides for the vehicle so if something is broken it will help you find out what the issue is and easy methods to repair it. You can then analyse if this can be achieved yourself or in the event the job is just too big you could book your MadAss 50 into a trusted mechanic.
Sachs MadAss 50 manual