If you want to do maintenance tasks for your Yamaha Raptor 90 then it is always a good plan to own a Workshop Manual to use as a reference in the event that you need to know simple methods to remove a specific component like the Drive Shaft and fit it again in the right way.
Yamaha Raptor 90 Workshop Manuals offer you certain diagnostic guides for your vehicle therefore if something is wrong it will help you work out what the problem is and ways to resolve it. Then you are able to analyse if this can be done yourself or in the event the job is simply too big you could make a reservation for your Raptor 90 right into a local friendly mechanic.
Yamaha Raptor 90 manual