Newbie with a speedfighter 3

Evening all im a newbie to bikes and scooters never had 1 so my knowledge is nil . Im going to have a read up and then hopefully i can put a post up later with a bit more knowledge to what im asking so i dont sound completely stupid. The reason ive joined is my son has a 50cc speedfighter 3 recently upgraded to a 70cc kit and we are not happy with the outcome so hopefully going forward we can figure out the problems thank u and i look forward to speaking to you all later