If you have to do maintenance tasks on your Aprilia Sonic 50 GP then it is always recommended to have access to a Workshop Manual to keep just for personal reference should you need to know easy methods to strip off a particular component like the Clutch and fit it again correctly.
Aprilia Sonic 50 GP Workshop Manuals offers clear distinct diagnostic guidelines with regards to your vehicle therefore if something is playing up it helps you ascertain what the problem is and the way to resolve it. You will be able to evaluate if this can be done yourself or that the job is too big you can still make a reservation for your Sonic 50 GP in to a suitable friendly mechanic.
Aprilia Sonic 50 GP manual