Reply To: GT125R Performance issues
It looks like one of the phases of the stator is on its way out. So I would most definitely look to upgrade the stator unit and regulator (being a married pair ofcourse lest old part ruins the new part)
Is the engine grey or black (OEM colour, not re-sprayed by past keepers) – if in doubt you can always upload the picture of the current stator thats in the bike , due to the fact there is 2 versions that exist
Also some owners actually buy newer flywheels and stators from a 2016 GT125RC to retrofit back inside a 2005-2010 engine.
Hence even on this site , i sell 2 variants of 125cc stators for the GT125 bikes.
I would definitely recommend NGK caps as the OEM caps are just rubbish. (Avoid the “plastic” ngk caps too as they rattle too much) , you want the rubber versions like we do and fresh plugs.
Coils = Keep the oem coils if the primary & secondary resistance are in spec ? (Measure the resistance of the coils without the HT cap attached. Poorly coils do make it hard sometimes to get up to speed if they are wanning (assuming she has had moments of misfire while riding ? or flat-ness in some rev ranges)
Tachometer = Post a picture , 3 variations exist and are tied to the harness the bike uses (as ofcourse there is 3 variations of harnesses Hyosung uses on the Gt125R)
Sorry for digressing , I hope i made some sense. In a nutshelf 85v + at 5k revs is good for a stator at all 3 yellow lines.