If you want to carry out auto repairs for your Yamaha XT660R then it is always recommended to have a Workshop Manual to use as a guide should you need to know tips to take out a specific part for example, the Exhaust and match it again successfully.
Yamaha XT660R Workshop Manuals gives you special diagnostic information on your car or truck therefore if something is playing up it can help you figure out what the situation is and how you can correct it. After that you can decide if this can be achieved by yourself or in the event the job is just too big you can make a reservation for your XT660R right into a suitable friendly mechanic.
Yamaha XT660R manual