If you want to undertake fixes on your Suzuki GSR 400 then it is always a great idea to have access to a Workshop Manual to use as personal reference if you want to know how you can take out a specific part such as the Brake Discs and match it again properly.
Suzuki GSR 400 Workshop Manuals offer you exact diagnostic guidelines on your automobile therefore if something is faulty it helps you identify what the situation is and some ways to correct it. After that you can assess if you can do this on your own or that the job is too big it is possible to make a booking for your GSR 400 in to a local repair garage.
Suzuki GSR 400 manual