If you want to carry out adjustments on your Aprilia ETX 350 then it is always a great idea to have a Workshop Manual to use as a guide in the event that you need to know the best ways to take out a certain part including Gearbox and install it again correctly.
Aprilia ETX 350 Workshop Manuals will give exact diagnostic details for the automobile so if something is wrong it helps you understand what the issue is and ways to fix it. You will be able to determine if you can do this yourself or in case the job is too big you can make a reservation for your ETX 350 in to a suitable car garage.
Aprilia ETX 350 manual