If you want to accomplish maintenance tasks on your Gilera NGR 250 then it is usually recommended to possess a Workshop Manual for personal reference in case you need to know the right way to take out a specific part including Drive Shaft and fit it again adequately.
Gilera NGR 250 Workshop Manuals provides targeted diagnostic guides for the car or truck therefore if something is playing up it will help you find out what the issue is and tips on how to correct it. Then you are able to evaluate if you can do this by yourself or if the job is just too big you could make a booking for your NGR 250 into a decent garage.
Gilera NGR 250 manual