If you wish to perform auto repairs to your TGB 303R 150 then it will always be recommended to have a Workshop Manual to use as personal reference in case you need to know how you can take off a certain part like the Brake Pads and match it again in the correct way.
TGB 303R 150 Workshop Manuals gives you targeted diagnostic facts for the car or truck therefore if something is faulty it can help you discover what the issue is and how you can repair it. You will be able to assess if this can be achieved by yourself or in the event the job is simply too big you can actually book your 303R 150 in with a trusted car garage.
TGB 303R 150 manual