If you want to do maintenance tasks for your Yamaha YFM90 then it is always a good idea to have a Workshop Manual for reference just in case you need to know the best way to remove a certain part like the Dashboard and install it again in the right way.
Yamaha YFM90 Workshop Manuals can provide specified diagnostic wisdom on your car therefore if something is wrong it can help you ascertain what the situation is and methods to repair it. After that you can determine if you can do this by yourself or in the event the job is simply too big you can actually make a booking for your YFM90 in to a trusted garage.
Yamaha YFM90 manual