If you wish to accomplish maintenance tasks for your Honda CB 400 A then it is usually a good idea to own a Workshop Manual to keep just for personal reference in case you want to know how you can take out a specific part such as the Brake Discs and install it again in the right way.
Honda CB 400 A Workshop Manuals are able to offer detailed diagnostic facts for the automobile therefore if something is playing up it helps you determine what the issue is and how you can fix it. You can then evaluate if this can be achieved by yourself or if the job is too big you can book your CB 400 A right into a nearby garage.
Honda CB 400 A manual