Don't order a new tb, try to narrow precisely what is binding by taking the quadrant off etc to see if it is the spindle binding, or may even just need some usual road grime grit cleaning off the linkage, could try a serious spraying with wd40 etc, then re oil afterwards.
I'm assuming yours is cable throttle, can't remember if they are, or fly by wire, sur eit's cable though.
tabetha