I'm thinking about buying a used cb750 sohc big bore kit. One of the sleeves is cracked, but it comes with another jug with three good sleeves, and the guy says a sleeve can be pressed out of the one jug and put in the other. Is this true? Also, he says the pistons measure 66.5mm and the bores measure 67.15mm. Is this within spec? It sounds a little worn to me , but I don't know what the clearance should be. Finally, assuming the kit is usable, can I get rings for this? Thanks, Jimmy.