If you wish to conduct maintenance tasks on your own Triumph T 140 E Bonneville Executive then it is always a good idea to possess a Workshop Manual to keep just for a guide if you need to know the best ways to remove a certain component such as the Gearbox and match it again efficiently.
Triumph T 140 E Bonneville Executive Workshop Manuals provides detailed diagnostic guidelines for your car so if something is faulty it will help you figure out what the issue is and methods to resolve it. You will be able to decide if this can be achieved on your own or if the job is too big you can book your T 140 E Bonneville Executive in with a trusted mechanic.
Triumph T 140 E Bonneville Executive manual