Reply To: Begins to die at high rpm under load – GT250
It might sound stupid, but have you taken the “Slides Off” (carb diaphragms?) , what if it revs past 7k, then the slides stick ? incase they are too scratched up (then its time for a new set) and also verify the mixture is around 2.5 full turns out each carb , and leave it there forever.
Test ride it again, to see if it helps.
And also try this free mod (Slide Tuning Mod)
Also have a can of carb cleaner, when she is idling and revving, spray carb cleaner around the airbox and intake pipes = Do the revs change ?
If yes , your airbox is loose
Or the intake O-Rings are shot , meaning as soon as lot of air is sucked in to the bike (full throttle), the slides hang due to excess air still passing through ?
Like these little ones (if its a 2004, it is probably time to change the o-rings), like these you see here
Intake Pipe O-RING (Inlet Boot Seals) x2 – GV125 GT125 RX125 GV250 GT250 Hyosung
If we can confirm 100% the intake & carb side is all good. Then we can progress to the electrics.