If you wish to accomplish fixes on your Honda CB 400 T then it is usually a good idea to own a Workshop Manual for personal reference in case you want to know ways to strip off a particular part for example the Brake Discs and fit it again in the right way.
Honda CB 400 T Workshop Manuals gives you certain diagnostic details for your automobile therefore if something is broken it can help you identify what the problem is and the way to correct it. Then you are able to decide if you can do this by yourself or that the job is just too big you can book your CB 400 T into a local friendly mechanic.
Honda CB 400 T manual