If you wish to execute maintenance on your own Triumph Thunderbird then it will always be a good idea to own a Workshop Manual to use as a guide just in case you want to know how you can take out a certain part for example the Drive Shaft and match it again in the correct manner.
Triumph Thunderbird Workshop Manuals provides specific diagnostic details for your vehicle therefore if something is broken it can help you figure out what the problem is and tips on how to fix it. Then you are able to assess if you can do this by yourself or in the event the job is simply too big it is possible to make a reservation for your Thunderbird into a suitable car garage.
Triumph Thunderbird manual