If you wish to carry out adjustments for your Sym HD Evo 125 then it will always be a good plan to own a Workshop Manual to keep just for a reference just in case you need to know the right way to take off a specific part for example Brake Discs and install it again appropriately.
Sym HD Evo 125 Workshop Manuals provides specific diagnostic guides on your automobile so if something is broken it will help you work out what the situation is and methods to make it better. After that you can determine if this can be done yourself or in the event the job is simply too big it is possible to book your HD Evo 125 in to a decent mechanic.
Sym HD Evo 125 manual