If you need to conduct auto repairs on your own TGB 303R then it is always a good plan to have a Workshop Manual to keep just for reference in the event that you want to know tips on how to take off a specific component such as the Clutch and install it again properly.
TGB 303R Workshop Manuals offers clear certain diagnostic info with regards to your vehicle therefore if something is not working it can help you ascertain what the situation is and tips on how to repair it. You will be able to decide if this can be done yourself or in the event the job is simply too big it is possible to make a booking for your 303R in to a trusted friendly mechanic.
TGB 303R manual