Forums 🚥 PiT STOP 🔧 Hyosung Technical Help Umbau von Gt125r motor auf GT250 Motor Reply To: Umbau von Gt125r motor auf GT250 Motor
Apr 15, 2026 at 8:51 AM
#22333
Use 250 jets pilots and mains, because of bigger pistons, or it will be lean and burn a hole in the piston.
Don’t worry about the vacuum pump, all 125 / 250 are using 650cc pump – Hyosung uses a 650cc pump on their 125/250 motors. So if a GV650 can use the vacuum pump, your 250 will never max it out.
Good luck!