If you choose to perform fixes for your MZ SM 125 MIG then it is usually recommended to possess a Workshop Manual to keep just for reference if you need to know the way to strip off a specific component including Brake Discs and fit it again accordingly.
MZ SM 125 MIG Workshop Manuals can offer you distinct diagnostic guides for your vehicle therefore if something is wrong it helps you discover what the problem is and some ways to fix it. You will be able to decide if this can be achieved on your own or in case the job is simply too big you can book your SM 125 MIG in to a trusted car garage.
MZ SM 125 MIG manual