i have a problem with my mini chopper 49.5cc 4 speed auto, i had carby problems it being to big for the motor so i get it fixed, i took it back, when i was riding it was slow and high rev like it couldnt change gear so i was just riding slow down the road, i stopped for about 5mins started riding and it was allgood, now its doing the same thing going slow high reving etc HELP! i bought it recently year old mechanic said rarely used, when i bought it didnt really know much about bikes, when i first bought it ran it empty on petrol might of thought i effed up the clutch