If you need to do auto repairs on your own Suzuki GN 400 L then it is usually a good idea to possess a Workshop Manual to keep just for a guide in the event that you want to know how to take off a certain part including Exhaust and install it again perfectly.
Suzuki GN 400 L Workshop Manuals offers you special diagnostic guidelines with regards to your vehicle so if something is faulty it can help you understand what the situation is and how you can resolve it. You can then analyse if this can be done on your own or in case the job is just too big you are able to make a reservation for your GN 400 L in to a trusted friendly mechanic.
Suzuki GN 400 L manual