I have taken the head off and noted very badly eroded water jackets and the cylinders have some deep grooves/scores in them (assume the water from the corroded head has been sitting in the bores) so I have a feeling os rings wont be enough once the bores are machined. I assume the big/small end bearings will also be victims of the swarf from the cylinders, but I haven't taken the crank out yet to have a look. Somehow I don't expect it to be a simple as replacing valve guides! I sent Ernie a PM a few weeks ago to inquire whether he is still supplying bits and pieces, but I'll try again. (unless there are other local alternatives for good quality pistons rings and bearings)