If you choose to undertake repairs to your Suzuki DR Z 125 then it is always a good idea to have access to a Workshop Manual for a reference in case that you need to know easy methods to strip off a certain component for example the Gearbox and fit it again efficiently.
Suzuki DR Z 125 Workshop Manuals offers you specific diagnostic guidelines with regards to your vehicle so if something is wrong it helps you identify what the problem is and some ways to make it better. You can then assess if this can be achieved by yourself or that the job is too big you can actually make a booking for your DR Z 125 into a decent mechanic.
Suzuki DR Z 125 manual