If you wish to execute maintenance tasks on your own Motobi Velvet 400 then it is usually a good plan to have access to a Workshop Manual to keep just for a guide in case you need to know how you can take off a specific component for example, the Gearbox and fit it again perfectly.
Motobi Velvet 400 Workshop Manuals provides specific diagnostic info for your vehicle therefore if something is not working it helps you identify what the situation is and tips on how to repair it. After that you can assess if this can be achieved by yourself or if the job is just too big you could book your Velvet 400 in to a decent garage.
Motobi Velvet 400 manual