I will try and extend the life of this engine, the best I can with what I have.
Will take the engine to work to get the piston & bore measured accurately. Best I can get is 64 mm, for both.
I have done the cylinder honing & the GXV140 second ring end gap was 0.009" now 0.011".
Valves were in good shape, only need a little lapping.
I also checked the GXV140 rings, side clearance in the piston grooves, which are OK.
Will get back onto it in a few days.