Kieron31

A couple of week ago i was riding along at 60mph and all of a sudden my bike jolted and lost all power like the throttle had been shut off. Ever since this incident at about 6000/7000 revs in 4/5th gear it just loses all power and i cant get over 40mph on flat. 1st, 2nd and 3rd gears work fine but its when i need to go up a hill at 40mph that it just doesnt go. Does anyone know what may have happened?