If you wish to carry out fixes on your Yamaha YZ450F then it is usually a good idea to own a Workshop Manual to use as a reference in the event that you want to know the way to strip off a particular part like the Brake Pads and install it again in the correct way.
Yamaha YZ450F Workshop Manuals will give you precise diagnostic information with regards to your car or truck therefore if something is faulty it can help you find out what the issue is and the way to make it better. You can then evaluate if you can do this yourself or if the job is simply too big you could book your YZ450F right into a local garage.
Yamaha YZ450F manual