If you want to carry out fixes for your KTM Comet Grand Prix 125 RS then it is usually recommended to possess a Workshop Manual to use as reference in case you want to know techniques to take out a specific part for instance the Door and fit it again safely.
KTM Comet Grand Prix 125 RS Workshop Manuals can provide particular diagnostic facts for the automobile therefore if something is playing up it will help you determine what the problem is and the best way to correct it. After that you can evaluate if this can be achieved yourself or if the job is just too big you can actually book your Comet Grand Prix 125 RS in with a trusted mechanic.
KTM Comet Grand Prix 125 RS manual