left over from a project. I bought a chain and sprocket set for a project, turned out the project I had (CR125) had had its rear wheel swapped with a wheel from a different bike, so I have a brand new rear sprocket that didnt get used as it didnt fit.

$45

it was ordered for a 1991 model, but I think it will fit a variety of other years as well, and maybe the CR250 too?