Hi David:
I just took an old OS 61 FSR out of my Utter Chaos that was giving me trouble and I think we have the same sleeve. I have also rebuilt with new brgs and a ringed piston and liner.
It always amazed me how OS could make such a good fit of piston and sleeve and have good running motors out of the box but the plating NEVER came off the Enya's and others that took forever to break in.

Peace

Mark O