running weird

[RKZX2]

i have a 2008 UM 250xspeed (Hyosung MS3 250) i cannot for the life of me figure out what is wrong with it. it will stall for no reason. but only when i come to a stop. not all the time. it seems to idle low. i went through it as far as my experience let me. i changed the oil (Amsoil 10w-40) changed the air filter, cleaned the MAF, put in a new spark plug (an irriduim this time) i'm about to throw in the towel. i joined this forum to see if anyone might know what could be wrong with it. thanks.