If you need to do maintenance tasks on your Gilera NGR 250 then it will always be recommended to own a Workshop Manual to use as personal reference if you need to know ways to remove a specific component like the Dashboard and install it again appropriately.
Gilera NGR 250 Workshop Manuals provide you with specified diagnostic information with regards to your car therefore if something is broken it will help you understand what the situation is and the way to correct it. You will be able to assess if you can do this yourself or in the event the job is just too big it is possible to make a reservation for your NGR 250 into a local car garage.
Gilera NGR 250 manual