If you want to conduct adjustments for your Yamaha FZR 400 RR then it is always recommended to have a Workshop Manual to keep just for a guide if you need to know the way to remove a particular component for example Exhaust and fit it again the right way.
Yamaha FZR 400 RR Workshop Manuals gives you unique diagnostic guidelines with regards to your car so if something is broken it will help you determine what the problem is and tips on how to make it better. After that you can analyse if this can be achieved yourself or if the job is too big you can make a booking for your FZR 400 RR in with a decent garage.
Yamaha FZR 400 RR manual