Reply To: Bike Can Only Start If I Rev The Throttle – GT250R 2013
The ECU needs the temp sensor working, it helps it regulate how much fuel goes in there, if cylinder is hot , it tells ECU send more fuel to stop it going lean condition, and it controls your IAC (idle control valve stepper) when the bike is at idle too. It is not good to bypass it. Hyosung has used a small margin in their ECU map code , it means it can’t compensate too much or it shuts down to protect engine.
So i can’t advise a Bypass but , find in the service manual the highest resistance it takes and max temps (eg. 4,000 ohms at 100*C degrees ) and try to find a similar sensor that has the same readings at 25c, 50c , 75 , 100 etc, if it matches the service manual , then use it. Get your mechanic to match the thread on the engine , eg. OEM sensor takes 11mm threads and uses 1.5 pitch , then get a sensor that matches that.
Otherwise, hunt a damaged Hyosung in your country (crashed bike) , and get its ET sensor from them.
I have not yet found a replacement sensor that uses the tiny connector Hyosung uses. Most sensors for bikes and carbs use big plugs , so Hyosung made it difficult.
I would not cut your wires.
If you find a sensor with a different connector (as long as it matches OEM Ohms & Temps) ==> Get a spare “injector + ET” harness from any 250cc EFI hyosung in your country (GV250 / GT250)
GV650/GD250 use water sensors, so they will not work without making the job extra difficult retrofitting it. Some people tried to put a WTS (Water Temp Sensor) in to 250cc Oil Cooled ET port, they almost damaged the engine, so it is risky and almost not worth it.