Yes Rookie, I have always been mainly hooked on the red ones, Off and On Road!
Currently have a CR125RY just for a bit of fun with my youngest, but I'm also rebuilding an RA motor (slowly).
I am on the look out for an old RZ/RA basket case to play with.. the RH chain driven Elsinores are of the era I grew up in
I've googled websites, Ebay, David Silver in the UK etc, sounds like this washer was made obselete by Honda a long time ago, even the complete shafts I see on Ebay in the States do not seem to have them fitted (I think it must stick on the inside of the LH case on disassembly and gets lost/mislaid).
Even if I can get the thickness of one I could then make one up - it is just a plain hardened thrust washer..
Cheers,
Steve.