If you want to undertake adjustments on your own Yamaha YZ 250 F then it is usually a good idea to own a Workshop Manual to use as a reference if perhaps you need to know tips on how to remove a particular component much like the Door and install it again the right way.
Yamaha YZ 250 F Workshop Manuals will provide you with special diagnostic guides for the car or truck so if something is wrong it will help you ascertain what the situation is and how you can repair it. You will be able to evaluate if you can do this yourself or if the job is just too big you could book your YZ 250 F right into a suitable mechanic.
Yamaha YZ 250 F manual