Dont think such a record was attempted with a CR125, karts have been banned from the flats for a while too. CIK bodywork is about as aerodynamic as a house gable so to be honest, the top speed would prettymuch be the same at the salt flats or Daytona, power to drag ratio is pretty poor. Start laying back and down though and things change significantly.
It’s all about aero, I believe there was an 80 cc (maybe even 50cc) two stroke turbocharged bike that topped 140 some time ago on the salt flats. Ive also seen a picture of a kart that the driver was laying completely flat on stomach, facing forward. Get a CR125 on that and you should be humming along at 140ish.
But otherwise, I don’t believe such an attempt was made before karts were excluded from the salt flats.