Topic: Single piston ring replacement

[zojirushi]

Hey Folks,

I tore down my '72 CB500 to replace a sagging primary chain.  PO told me she was overbored .25 about 10K ago.  Compression was between 135 and 140 cold.  While removing the pistons I noticed the second from the top ring was broke on cylinder 3.  A new set of rings is on its way, but my question is what needs to be replaced?  Can I replace the single ring and button her back up?  Does she need a honing for a single ring?  More?  Less?  Other?

[lrutt]

You should replace all 3 and glaze break the cylinder. You won't get a ring seat if the cylinder is polished down, plain and simple.

If it were me I'd have probably done all 4 and check the valves for leakage as well. That's easily done and they could be lapped in quickly if need be.