If you want to do maintenance on your Derbi DXR 250 then it is always a good idea to own a Workshop Manual to use as personal reference should you want to know tips to take out a certain part like the Drive Shaft and fit it again effectively.
Derbi DXR 250 Workshop Manuals can offer you special diagnostic information for the car so if something is wrong it will help you work out what the situation is and the way to correct it. You will be able to assess if this can be achieved by yourself or that the job is too big it is possible to make a booking for your DXR 250 in to a trusted car garage.
Derbi DXR 250 manual