Reply To: Slow throttle response on low throttle – GT250Ri
Hmm in Spain, go find this bottle (this exact bottle) and get 2 of them (yes 2 of them)
https://www.halfords.com/motoring/engine-oils-and-fluids/fuel-and-oil-additives/wynns-formula-gold-petrol-treatment-500ml-166754.html
Drive with both bottles filled in the tank and also about half a tank of E5 fuel (5% ethanol? here it’s called premium fuel in UK) as the cheap ones (standard fuel) %10+ ethanol is just not good on Hyosungs , although it will run E10 fine but nothing positive for any vehicle using too much ethanol but i am digressing.
Observe her, the idea is to try clean out your entire fuel system critically the pump and the injector. I know myself that when i increase the throttle, the pump gets louder , what if your fuel pump has some kind mini-delay to the throttle response or the injectors are waning ? TPS would be the last thing we check but it is also worth checking to make sure it is in OEM specs with your multi meter as per manual guidance.
If the tank is nearly empty, siphon the fuel out of the tank carefully, and inspect your fuel pump or the fuel strainer being clogged, it gets clogged eventually causing the pump to work harder than it needs to or slightly less pressured fuel going to the injectors.
Least if the 2 bottles get used on the tank, its one less maintenance thing to do knowing you had the bottles try to clean out the fuel parts.
Another tip , spray carb cleaner (be wise! ⚠️🔥) around the intake pipes , so see if there is an air leak (even a tiny bit) , these O-Rings eventually do need replacing to keep things optimal:
Intake Pipe O-RING (Inlet Boot Seals) x2 – GV125 GT125 RX125 GV250 GT250 Hyosung
Also , check your ISCV O-ring on the airbox, like this example below:
GV125s idle speed when hot / ISCV problem (Idle Speed Control)