If you want to perform maintenance on your own Derbi Senda Baja 125R then it is usually recommended to have access to a Workshop Manual to use as a reference just in case you want to know tips on how to remove a particular component including Drive Shaft and install it again successfully.
Derbi Senda Baja 125R Workshop Manuals will give you particular diagnostic wisdom for your vehicle so if something is playing up it will help you figure out what the issue is and some ways to repair it. You will be able to decide if this can be done yourself or that the job is too big you can still make a booking for your Senda Baja 125R into a local car garage.
Derbi Senda Baja 125R manual