Topic: Do I need to replace my rings?

[jekslek]

Hi everyone. A bit of a philosophical question. I am in the midst of rebuilding a CB550F. I decided to take apart the top end of the engine to check for general wear and tear, do some cleaning, and replace the gaskets. The Pistons had a little bit of carbon buildup, but nothing that a little hand scrubbing and dremel-ing couldn't take care of.

I have been debating on whether or not to replace the rings. The cylinder walls are smooth with no visible scratches or marks. I keep thinking that I MIGHT AS WELL since the rings are most likely original, I have the engine taken apart this far, and the engine has 34k miles on it. Despite the high miles, everything looks like it's in good shape.
This is my first rebuild, but luckily I have a friend who has rebuilt the same bike. He insists that the rings are fine and I shouldn't worry too much about it. I didn't run a compression test before disassembly because everything seemed within decent working order. I would love to skip putting the new rings on, but I don't want to be kicking myself for not doing it in the near future.

SO. Should I replace the rings? If I do, will I have to get the cylinders honed (not bored)? Because of the COVID outbreak my local shops are mostly closed, and I do not have the tools to hone the cylinders properly and I'd like to avoid doing any damage by going the diy route. If I were to put new rings on without honing, would that defeat the purpose or cause damage? Is the purpose of honing to break in the new rings?

Apologies for the many questions. Thank you for the help!

[69cb750]

Use new rings, buy hone from http://www.brushresearch.com/
Hone works with drill, puts cross hatch in cylinder so rings will seat.
Check cylinder is smooth near top, no step.

[dhall57]

I have the engine taken apart this far, and the engine has 34k miles on it. Despite the high miles, everything looks like it's in good shape.
 I didn't run a compression test before disassembly because everything seemed within decent working order.

By what your saying here and correct me if Im wrong but you talk like the motor was fine. I hope you didn't decide to go into it just because it has 34k on it. These miles are nothing if the bike has had any type of maintenance over the years and hasn't been used and abused. Welcome to the forum jekskek and good luck with what ever you decide to do

[PeWe]

If pistons, rings and bores are fine without deep scratches, rings not wiggle up down in pistons.
I should use a flex hone brush grit 240 and give bores a quick rough crosshatch pattern. 10-15 strokes up-down with a drilling machine, brush lightl oiled. No new rings, just as is.

Head might need a valve job when you have parts apart?

[MauiK3]

I'm one of those that obsess about consumables such as rings. If I'm in there, consumables get renewed just the same as gaskets and o rings. It's just me.
Hone for sure.
Check valves, the seals and guides would be another thing would be hard pressed not to take care of.

[Jerry Rxman Griffin aka MuthaF'er]

Check the ring end gap. If good light hone the cylinders.

[PeWe]

If rings are too worn, a cheap oversize piston kit from www.cruzinimage.net will probably not cost more than stock rings.
Only the small additional bore with tight clearance like 0.025mm/0.001".