If you wish to perform adjustments on your own Yamaha Majesty 125 then it is always recommended to have a Workshop Manual to keep just for personal reference in the event that you want to know ways to take off a certain part for instance the Gearbox and match it again in the correct manner.
Yamaha Majesty 125 Workshop Manuals can offer you specified diagnostic information for your vehicle so if something is broken it helps you figure out what the situation is and how you can repair it. After that you can determine if you can do this by yourself or that the job is just too big you can still make a reservation for your Majesty 125 into a suitable friendly mechanic.
Yamaha Majesty 125 manual