If you want to conduct repairs to your Tomos SM 125 F then it will always be a good plan to own a Workshop Manual for a reference in case you want to know techniques to strip off a certain component much like the Clutch and install it again safely.
Tomos SM 125 F Workshop Manuals are able to offer detailed diagnostic guides for the vehicle therefore if something is broken it will help you identify what the issue is and how you can fix it. Then you are able to analyse if you can do this on your own or that the job is too big you can still book your SM 125 F into a local garage.
Tomos SM 125 F manual