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Hone cylinder for new rings?
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Author:  Bugman Jeff [ Tue Aug 14, 2012 10:32 pm ]
Post subject:  Hone cylinder for new rings?
There are no stupid questions, but there are a lot of inquisitive idiots :wave: I have to replace the rings in my new used KH100('cause I broke one replacing the base gasket :roll: ) Now, every time I've had a 4 stroke apart and put new rings in it, I've honed the cylinders, it's just what you do. But, I've never re-ringed a 2 stroke. Should I hone the cylinder, or just put it back together as is? If it should be honed, I assume that because of the ports in the cylinder, I'll need to use a bar hone? Thanks for the help.
Author:  BarryB [ Tue Aug 14, 2012 11:10 pm ]
Post subject:  Re: Hone cylinder for new rings?
I always hone, a few quick passes is all you should need - get the cross-hatch back, and done. Anything more than that is "more than that"... I use a ball hone.
Author:  Jackman [ Wed Aug 15, 2012 4:21 am ]
Post subject:  Re: Hone cylinder for new rings?
I used a NAPA ridged hone but ball hone is better, after honing lightly sand the port edges to take that sharp lip off so your new ring does not get hung up on a port,,,
Author:  Leemata [ Wed Aug 15, 2012 6:17 am ]
Post subject:  Re: Hone cylinder for new rings?
Definitely use a ball hone. I suggest you use 240 grit in a size that's 20% larger than your bore.

You can find them here.

http://www.mcmaster.com/#ball-hones/=iuwg8b

Terry
Author:  Steve [ Wed Aug 15, 2012 8:09 am ]
Post subject:  Re: Hone cylinder for new rings?
http://www.brushresearch.com/pdf/GB.pdf
Author:  rusty34 [ Wed Aug 15, 2012 9:11 am ]
Post subject:  Re: Hone cylinder for new rings?
I worked for Sunnen about 25 years ago so I know a little about honing and might possibly be qualified to comment on this one. When changing the bore size on cylinders with ports they should be bored close enough to the finish size so that only enough stock is left to establish the correct surface finish with the hone. The reason for this is the honing process involves not only stock removal but stone breakdown as well. The two always work together so that the honing stones and guideshoes stay straight and the cylinders stay straight and true. The problem arises with an interrupted bore. Rate of stone breakdown is different over ports and stock removal is greater around ports. In layman's terms this means excessive honing will create a bellmouth condition around each port which will interrupt ring sealing. I don't have any experience with a "berry" hone but lots of folks probably use them.

regards, Rusty34
Author:  Ja-Moo [ Wed Aug 15, 2012 10:26 am ]
Post subject:  Re: Hone cylinder for new rings?
A ball hone isn't necessary. As Barry said, you are just scratching the bore, not trying to remove metal. 4 or 5 up/down passes is all that is needed......
Author:  rusty34 [ Wed Aug 15, 2012 11:41 am ]
Post subject:  Re: Hone cylinder for new rings?
I agree. You might also see what the ring manufacturer recommends for surface finish in order to select the correct stone grit size. I don't know how it is for motorcycle rings but I can say in the case of many new modern automotive rings there is no recommended break-in period anymore. During manufacture rings are lapped to a specific size and finish and are ready for full power right out of the box as long as cylinder wall preparation meets the ring manufacturer's standards.

Rusty34
Author:  Leemata [ Wed Aug 15, 2012 12:13 pm ]
Post subject:  Re: Hone cylinder for new rings?
I recommended a ball hone because they are not as likely to hang up in the ports. The 240 grit was recommended to me by Eric Gorr, a well known 2-stroke (mostly dirt bikes) tuner.

I agree.....4 or 5 quick passes should do it. I once honed a friend's '98 CR250 cylinder in the parking garage of the old RCA Dome in Indy.

Terry
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