Lemon joose

Thanks for replying the air filter has been replaced by the previous owner from a filter box to a mushroom type I will return to stock when I find the correct part but didn't know it would have made such a difference I think the carburetor jets have remained stock pilot is a 38 but can't see a number on the main jet.

Hi I am having trouble with my 2006 kymco ck125 it wont accelerate past 25 mph it starts fine but doesn't go the speed limit. I have replaced the spark plug, tested the coil cleaned the carburetor, fitted new fuel filter, changed the cdi, tested the stator, changed the fly wheel ( the one fitted was stamped honda cg125 ) and done valve clearance also fitted new clutch friction plates it is running fresh oil the tach reads 22176 it gets to around 30 mph then stops accelerating the revs dont go higher then power drops off I have go into 3rd or 2nd gear to maintain speed.please can anyone help what have I overlooked