RM125 Bogging Problems Need Help

i have a 2006 RM125 the has a bogging problem. i just had the top end rebuilt less than a month ago and the bike starts first kick. when i ride the bike and let the clutch out the bike bogs almost to the point when it shuts off, or when im riding and slow down almost to a complete stop the bike bog. i brought the bike to a mechanic thinking my jetting was off and when he put the new jets into the bike it did not fix the problem. someone please help if they no how to fix this problem.