If you wish to accomplish adjustments on your own Hyosung GT 650 S then it will always be recommended to have access to a Workshop Manual to use as a guide in the event you need to know techniques to remove a certain component including Gearbox and install it again in the correct manner.
Hyosung GT 650 S Workshop Manuals are able to offer identifiable diagnostic facts on your automobile so if something is broken it can help you identify what the issue is and some ways to correct it. You will be able to decide if this can be done on your own or if the job is just too big it is possible to make a reservation for your GT 650 S in to a decent car garage.
Hyosung GT 650 S manual