overboost93

Hey. I got a Beta Rev3 from around 2002-2003- with a 250 ore 270 cc engine. It runs very well at idle , but when I speed, it begins to shoot in the exhaust and go bad . What could this be? I have new spark plug , fresh gasoline . cleaned the carb . Im not sure if the pilot jet is correct adjusted. I did try first with 1 round, then 1,5, then 2 and then 2,5 and then 3 turns, but nothing helped. Any tips? Second thing, Im not sure how old this bike is, i got a frame number x ZD3B9000Y0002660 x Anyone who can help me translate that frame number? On the engine side its written 352C/1 0 1/1. It go ta Mikuni carb Just to be sure, The pilot yet is the little screw i mark with a red dot on the picture right ? Thanks from Norway!