my bike is a 2001 aprilia rs125 with 15000km on the clock and i know they don't have much drive before 7000rpm normally but it's lost a consideral amount of power and is running like crap at the moment. i have just put a new tank of fuel in and cleaned the power valve. I will change the spark plug today does anyone else have any ideas about what could be wrong ?? I am not very mechanically minded but the bike has been ridden for the past 6 months without missing a beat and is always topped up with the best oil. Any help would be greatly appreciated!!