If you need to do fixes for your Honda TRX420FA then it will always be a great idea to possess a Workshop Manual to use as personal reference if you need to know proven methods to take off a specific component for instance the Brake Discs and install it again correctly.
Honda TRX420FA Workshop Manuals can provide unique diagnostic wisdom on your car therefore if something is faulty it can help you identify what the situation is and the way to make it better. You will be able to evaluate if you can do this on your own or in case the job is simply too big you can make a booking for your TRX420FA into a trusted friendly mechanic.
Honda TRX420FA manual