If you have to undertake maintenance to your Hyosung GT 650 S then it will always be recommended to own a Workshop Manual for a guide in the event you need to know proven methods to strip off a particular part such as the Gearbox and install it again in the correct manner.
Hyosung GT 650 S Workshop Manuals are able to offer special diagnostic guidelines with regards to your car so if something is not working it will help you ascertain what the issue is and how to correct it. You can then assess if this can be achieved yourself or in the event the job is simply too big you are able to make a reservation for your GT 650 S into a suitable friendly mechanic.
Hyosung GT 650 S manual