Topic: reusing piston rings?

[Jay B]

My 350f is using some oil in #2 jug, probably guide and seal, although I haven't tested it yet (will be a winter project) I'm sure I will be removing the head (again) I'd like to take the cylinders off also for a new gasket and possibly a new cylinder stud. These rings have about 2k miles, obviously if I remove the jugs they will be turned differently in the bores on reassembly. Could I just re-hone and use them again? Standard size rings don't come up on eBay too often, and damn they are expensive from Honda. TIA

[scondon]

      I recently had to teardown my top end after 1,500 miles on fresh rings/bore. I didn't re-hone or add new rings and haven't had any problems. I am curious what others have to say on the subject.

[Gordon]

I know it's not recommended, but when rebuilding my 750, due to extremely limited funds, I didn't replace the rings or hone the cylinders after dismantling the engine.  It had about 22K on it at the time, it's been over two years and about 13K miles and never had any problems.  I probably wouldn't do it again, but it didn't hurt that time.   

[Bodi]

With that low a mileage on them I would just reassemble without any honing. Unless the cylinder is oval or some other oddness they will seal fine even though the gaps are at a new spot.

[aptech77]

I don't think honing would hurt, but if you don't hone, MAKE SURE everything goes back in its same location.

[bryanj]

OK Heres somthing for you to think about:-
Rings do not sit in one possition for life they rotate arround the piston which is why strokers have the rings pegged to stop it!

If its running ok and bores are good do not hone unless they apear "shiny" and glazed

Rings are ok unless they are worn, Either diametricaly or thickness wise

[crazypj]

I found that due to my riding style (500rpm below redline most of the time ) I needed new rings in the 550 (591cc) kit every 10,000 miles. I have re-used rings without any problems. Most manufacturers dont give a free end gap which gives an indication of ring tension in bore (the fitted gap tells you if they are worn but not if there is enough tension to seal properly) On most Honda's 'we' deal with  its going to be around 8mm~10mm free gap. Does anyone have any new rings to check with? ( I've just measured some 1mm OS piston rings for CB750 which are 10mm free gap) I think on the smaller bore it may be OK to have as little as 6mm free gap ( but I'm just guessing/experience)
PJ

[Tim.]

Rings do not sit in one possition for life they rotate arround the piston which is why strokers have the rings pegged to stop it!

Yep - that's what I understand as well - all this talk about ensuring the gaps on the different rings are 120 degrees apart etc. is really not all that important.  Rings move.  I'd reassemble and space the gaps, but they're going to move anyhow and could just as easily spend some time aligned anyhow.

[MRieck]

I found that due to my riding style (500rpm below redline most of the time ) I needed new rings in the 550 (591cc) kit every 10,000 miles. I have re-used rings without any problems. Most manufacturers dont give a free end gap which gives an indication of ring tension in bore (the fitted gap tells you if they are worn but not if there is enough tension to seal properly) On most Honda's 'we' deal with  its going to be around 8mm~10mm free gap. Does anyone have any new rings to check with? ( I've just measured some 1mm OS piston rings for CB750 which are 10mm free gap) I think on the smaller bore it may be OK to have as little as 6mm free gap ( but I'm just guessing/experience)
PJ

10mm end gap...that's about .400 (approaching 1/2")!

[Gordon]

10mm end gap...that's about .400 (approaching 1/2")!

I'm thinking he forgot a decimal point in there somewhere.

[crazypj]

I didnt forget anything.
Read ALL the words.
The FREE end gap is when you remove rings from piston and measure the end gap.
The INSTALLED gap is when you fit piston ring into cylinder and measure the gap.
If the FREE gap is too small it means rings have probably been overheated, lost tension and will never seal correctly, even if installed gap is correct
Now you all learned something.
PJ

[Gordon]

Got it.  Now I'm smarter!

[Jay B]

Hmmm.... I figured rings wore into the cylinder walls and didn't move around the bore. That's why I was concerned about fitting them back in. 350f rings appear to have maybe 6mm or so free end gap (from memory) but you need to spring them out further than that to get them over the piston. On such a small piston you need to be really carefull not to break them.

[johnny-from-bel]

      I recently had to teardown my top end after 1,500 miles on fresh rings/bore. I didn't re-hone or add new rings and haven't had any problems. I am curious what others have to say on the subject.

Same here. While the piston goes up and down the rings have a tendency to rotate a bit so their wear on the cylinder is quite even.