If you choose to do repairs to your BMW R 850 Avantgarde C then it is always recommended to have access to a Workshop Manual to use as reference in case you need to know simple methods to remove a particular component much like the Door and install it again in the correct manner.
BMW R 850 Avantgarde C Workshop Manuals will give you exact diagnostic details on your automobile so if something is wrong it can help you understand what the situation is and tips to repair it. You will be able to evaluate if this can be done on your own or if ever the job is too big it is possible to make a booking for your R 850 Avantgarde C right into a suitable garage.
BMW R 850 Avantgarde C manual