Here we have for sale a CTC Yamaha TY250/350 Mono & TY250Z TK carb Throttle Screw Set 46Y-14103-00.
Manufactured to the exact same specification of the original Yamaha part that has now been discontinued and is no longer available.
The Throttle screw and spring have both been made from stainless steel.
Shown as number 16 on the parts diagram.