If you want to undertake repairs for your Triumph T 120 R Bonneville 650 then it is usually a good idea to own a Workshop Manual for reference in case that you want to know easy methods to strip off a particular component including Gearbox and install it again correctly.
Triumph T 120 R Bonneville 650 Workshop Manuals gives you exact diagnostic details for your vehicle therefore if something is playing up it can help you discover what the situation is and ways to repair it. You can then analyse if this can be done by yourself or in the event the job is just too big you can make a booking for your T 120 R Bonneville 650 into a local friendly mechanic.
Triumph T 120 R Bonneville 650 manual