Reply To: 2012 Hyosung GV250 EFI TPS Replacement
(mini)baby 6-sided sockets with a swivel works best , 12-sided sockets or spanners are not good. Spray a little bit of penetrant fluid on the bolts and leave to soak overnight, incase there is some kind of rust that was heat fused (joining the bolt and throttle body down) . Also 6-sided O-spanners work best , forget C-shape spanners as they always slip out.
TPS , here is some links that apply to the 250cc too
[Tutorial] How to replace Gt650r throttle position sensor (TPS)
Your TPS is held down by 1 bolt , but some models have TPS held down by 2 bolts, principle is the same. – Usually it is less frustrating to get a new one than trying to fix an old one , incase the rotating contacts inside the old TPS have broken down.