If you choose to conduct adjustments to your Honda CB 125 then it is always a good plan to have access to a Workshop Manual to keep just for a reference should you need to know proven methods to strip off a particular part for example Brake Discs and install it again accordingly.
Honda CB 125 Workshop Manuals provides distinct diagnostic guides on your car or truck so if something is wrong it will help you discover what the situation is and some ways to correct it. Then you are able to assess if you can do this on your own or that the job is too big you could make a reservation for your CB 125 into a trusted car garage.
Honda CB 125 manual