yx140 bearing issue

[SteveL]

I just bought a second hand yx140 thinking it just needed a new kick start shaft. When I split the center cases I found out the bearing had collapsed on the secondary gearbox shaft and damaged the bearing seat. There's no other damage so can I use my old gearbox and buy one of the newer right hand cases that use the needle roller bearing and replace just the case and fit the roller bearing. I've checked the ID of the old style bearing and the newer style needle roller bearing and both are 15mm.