Does anyone know where I could find this bearing? It's number 50 in the pic:

honda-crm250r-1991-m-japan-md24-120-e-8_big3IMG01149093_b61b by The Real Guy Photography, on Flickr

There should be a number on the bearing you are going to replace. 95% of bearing can be replaced using an internet bearing supplier.

Discontinued and a dodgy size. I think ntn might do one though in the correct size (24x56x15---- sc05a86) if not use Honda 91001-ML3-873 24x56x14 + 1 x 90452-KSR-A00 24x32x1mm washer on the input shaft

Thanks guys, that's really helpful! I just noticed #4 in the picture, any idea how crucial that gasket is?

That's the crankcase gasket that seals the 2 halves of the case, not sure why it's drawn like it's 2 pieces :/

OK phew, it's included in the gasket kit that I ordered! Thanks again