If you want to conduct auto repairs for your Derbi GP1 Open 50 then it will always be recommended to have a Workshop Manual to use as a reference if you want to know how to take out a particular component such as the Drive Shaft and fit it again efficiently.
Derbi GP1 Open 50 Workshop Manuals can provide specific diagnostic guides on your automobile so if something is wrong it helps you understand what the problem is and easy methods to repair it. After that you can determine if this can be achieved yourself or if the job is simply too big you can book your GP1 Open 50 right into a decent mechanic.
Derbi GP1 Open 50 manual