If you wish to perform maintenance tasks to your CSR NKT 125 then it is always recommended to own a Workshop Manual to use as a reference if perhaps you want to know ways to take out a certain part like the Exhaust and fit it again in the correct manner.
CSR NKT 125 Workshop Manuals are able to offer specified diagnostic details for your vehicle so if something is broken it helps you understand what the situation is and the way to repair it. After that you can decide if you can do this yourself or in the event the job is just too big you could make a reservation for your NKT 125 in to a nearby garage.
CSR NKT 125 manual