Hallo.
just want to know if it's possible to change the bushing for the idle gear kick start on a GY 6 engine?
See attachment

 

From the picture, it doesn't look like there is a bushing, I would guess the shaft turns in the aluminium case. It may be possible to bush it, but drilling the case out to take a bush risks weakening it. Not sure about the GY6 but Minarelli clone engine kickstarters are only for "get you home" emergencies and wear rapidly if you use them instead of the electric start, for any length of time.