Hone cylinders when reusing old rings?

[Nessism]

Engine in generally good condition. Bores look good. Ring end gaps within spec.

Compression unknown but assumed good. Pulled engine apart due to storage rot and head gasket leak.

Hone or no hone and why?

 

[blowerbike]

can you sneek a GS750 kicker engine in there?
i won't tell nobody
oh,
and yes ball hone and reassemble...
why?
gives the rings a second life or ummm...it just seems right and i always have myself.
if you was away from home doing a repair then i'm sure you could get by just putting it back together.

 

[tkent02]

I do it that way, the ball hone. But I like any excuse to break it in. ( Run the **** out if it! )

Is this the Kawasaki?

One more thing, if you don't know why it was parked eons ago, it may have been parked because the rings were not ever broken in correctly ( run the **** out of it ) it may have had low compression all it's life. Seen this a couple times now. Rings not worn, everything looks fine but they just never sealed. My old GS750, the one that got the 1000 transplant had very low compression and was slow as molasses. Low miles, the guy said it had always ran that way since new. I asked how he broke it in, he said he rode it super easy, never ever opened the throttle.

 

[rustybronco]

Didn't hone the cylinders on my 1980 '850 which had 33K when I tore it down and re-assembled it. No issues with the rings sealing. Tore Stan's GK down and re-assembled it without honing the cylinders. Haven't fired it up yet because the PO stripped the bolt holes holding the cam cover on and I need to pull the head again so the head can be properly drilled on a drill press for perma coils.

As long as the engine didn't have any oil control or compression issues before hand, the cylinders and pistons show no evidence of damage, I see no reason hone the cylinders if everything is in spec. If in doubt, a leakdown test can be performed to confirm.

Shall I ship you my ginsued device, or would you like to make your own?
http://www.thegsresources.com/_forum/showpost.php?p=1559962&postcount=1

EDIT>>> If it were a paying customer I'd hone it and install new rings.

 

[Guest]

I'm no epxert but I do not hone. The original rings are already broken in and honing to reseal will do little since the rings have already worn down the little high spots during the initial break in. Although I've never tested the theory, I would suspect this would reduce overall compression numbers since you will not be able to achieve another break in.

 

[tkent02]

I would suspect this would reduce overall compression numbers since you will not be able to achieve another break in.

Yes, you can break it in again if you hone the cylinders. If you know it had good compression before that's one thing, he has no idea on this engine.

 

[Guest]

Cylinder Honing
Naturally, honing cylinders is part of boring them (although Yoshimura is said to have experimented with super-fine boring equipment in an effort to eliminate the honing step; it reportedly did not work) because what prevents simply boring to the correct size are the tool marks the boring machine leaves (not to mention the "cross-hatch" that should be imparted). But even a cylinder that is bored correctly, and there aren't many, often gets ruined on the hone. The best way to hone a cylinder is on a floor-mounted hone such as a Sunnen. A portable hone can work, but it won't do as nice a job, and getting close to as nice will be ten times as difficult. One thing that startles me even now is when I see or hear of folks using these same hones for "freshening up" purposes. Uh uh. A straight, mounted-stone hone is never to be used for anything but the sizing procedure after a fresh boring. Any other use is "hack" in the powersports industry. It is far too aggressive to use this kind lf hone for ring-seating. First, there are special hones (two different kinds, in fact) for deglazing a cylinder for fitting new rings to an old cylinder, hones that remove virtully no cylinder material in the process. Second, if reusing the same rings and they can be matched to their original cylinders, no honing is needed or recommended. I see this all the time on forums where folks are talking about honing their cylinders, usually with brake cylinder hones. Think about it. Less than 0.001" factory clearance, and the break-in tin plating long gone from the used rings.

 

[tkent02]

It has worked for me, have not had one that didn't seal up and give good compression.

 

[blowerbike]

how do i want to say this...
bear/bare? with me
theory is one thing but actually doing it and being able to state the facts of what works and what does not is what i go by.
i think that's what i mean??

 

[TeamDar]

Use a ball hone. If you don't and the rings don't seal you will be sorry and have to take it apart to do it right.

 

[GregT]

I do it that way, the ball hone. But I like any excuse to break it in. ( Run the **** out if it! )

Is this the Kawasaki?

One more thing, if you don't know why it was parked eons ago, it may have been parked because the rings were not ever broken in correctly ( run the **** out of it ) it may have had low compression all it's life. Seen this a couple times now. Rings not worn, everything looks fine but they just never sealed. My old GS750, the one that got the 1000 transplant had very low compression and was slow as molasses. Low miles, the guy said it had always ran that way since new. I asked how he broke it in, he said he rode it super easy, never ever opened the throttle.

So very, very true...run the **** out of it....but do it on straight mineral oil too. Once re broken in, if you wish you can go to synth but not before.

 

[Nessism]

The engine in question is a KZ750 I'm restoring. Leaning toward a light hone. Thinking about 320 grit. Pulled off the cylinder tonight and noticed some light rust and some odd wear marks. Pistons don't have a spec of color on them so there couldn't have been much blow by.

 

[Steveb64]

Sometimes a hone to clean up the 'step/lip' that forms above the top of the stroke of the top ring is needed. Though I think (I'm not sure here) there may be 'special' tools to do this?

Re the carbon on the bores and pistons - CRC Gasket Stripper works wonders. Spray it on, wait a few minutes, and wipe it off. No scraping (which means no worry about scratches) needed. I discovered it by accident (cleaning old head gasket off) when working on my Mitsubishi engine a couple of years back. Does a great job of removing the carbon 'ring' at the top of the bores also. Then you can see how much of a 'lip' has formed.

DON'T get it on your skin though! Gloves and safety glasses/goggles at a minimum. Nasty stuff. Eats skin.

 

[rustybronco]

Sometimes a hone to clean up the 'step/lip' that forms above the top of the stroke of the top ring is needed. Though I think (I'm not sure here) there may be 'special' tools to do this?

Yes there is a tool for removing the carbon/ metal build up at the top of the cylinders. It's called a ridge reamer.

 

[rapidray]

If it is a restoration, & rings ARE fairly inexpensive, why is this even a question on an UNKNOWN engine? New rings & a correct hone is the RIGHT way to do it. Ray.

 

[Nessism]

This engine has 10k miles on it. Pistons look good so sealing seems decent.

New rings are $45/hole + shipping.

I ordered a ball hone today and plan to reuse the rings. Worst case is the engine gets torn down twice. Bought a brand new OEM head and base gasket for same price as one set of rings. Worst case is this is a $45 gamble.

 

[tkent02]

To measure the ring's end gap and tension you need to remove them. I can see just going by the fact that it's low miles, but who knows, the PO could have never changed the oil, ran it without an air filter, perhaps ran it 110,000 miles. If you are willing to risk pulling the head again, which is really easy if it hasn't been run much, go for it. I'd rather pull the rings off to inspect them. Ray's point is a valid one, rings are more than some parts but not really a bank breaker.

There was someone on this forum selling inexpensive piston rings a few months ago, do you remember that thread?

 

[koolaid_kid]

Ed, if you actually do end up re-doing the top end, you can pull the cylinder block and install it without pulling the engine out of the frame. In fact, when you go back together, I highly recommend installing the cylinder block after bolting the cases into the frame. One man job due to the lighter weight, a lot more clearance.

 

[Steveb64]

Yes there is a tool for removing the carbon/ metal build up at the top of the cylinders. It's called a ridge reamer.

I knew someone would have the answer! It's been a few decades since I've had an engine that would even need something like that (my Ducati has plated bores), but I had a vague recollection of something... :-k

 

[MrFreeze60]

And a word of advice, use a good quality break in oil after a rebuild or after a fresh top end.
I made the mistake of running regular oil after I rebuilt my 375 HP 327 years back. I went through it top to bottom with new everything, and I put 10W40 oil off the shelf in it, and drove it. Rings never seated, and I wiped out the cam after less than 50 miles.
After that EVERY time I rebuilt an engine, no matter if it was a bike or ATV engine, or a car engine, I put break in oil in it, and went by the manufacturers specs, and haven't had a failure yet.
And yes I know oil is a lot better than back then, but it's still good practice to do it right the first time. That way there is no need for a teardown.