If you have to conduct adjustments on your Sym Citycom 300i then it is usually recommended to own a Workshop Manual to use as a guide in case that you need to know how you can take out a particular part such as the Dashboard and fit it again adequately.
Sym Citycom 300i Workshop Manuals offer you certain diagnostic guidelines on your car so if something is not working it can help you understand what the problem is and methods to correct it. You can then decide if this can be done yourself or if ever the job is too big you could make a booking for your Citycom 300i in to a suitable car garage.
Sym Citycom 300i manual