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strichzwei
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Joined: 09/20/2012
Posts: 30

Guys, pulled this from my R80ST with 40K miles to rebuild heads (valve recession) and top end reseal. These are Nikasil cylinders so, as I understand it, cast iron rings. The 2nd ring is chipped on the end as you can see in the photo. To me, it looks like this was done a looooong time ago, maybe at the factory......but, I do not know for sure.

Compression was good on these when I took everything apart, sooooo the million dollar question - would you guys reuse this or re-ring the nikasil cylinders and hope the new rings seat alright (cross hatching in cylinders still very pronounced!)?

Thanks,
scott

  • piston_ring.jpg
schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6546
If it were me, I'd rering and

If it were me, I'd rering and use the proper honing method to knock any glaze off the Nikasil.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

jrapose
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VBMWMO #8617
Joined: 02/12/2007
Posts: 263
I sure would replace that

I sure would replace that ring... it is a lower ring so replacing it would not have any affect on the cylinder... It does look like the ring was defective from the factory .... and has been in that condition for a long while... if it did not damage the cylinder...(scratch) then I would replace just that one ring... If you decide to do a total re-ring job then you will need to address the ridge at the top of the cylinder... but to replace that lower ring nothing else needs to be replaced.... If you do a total re-ring job then you probably should also have the heads done....rings and valves wear at about the same rate...increase the pressure/vacuum of one will cause the other to burn oil... just replacing one ring will not affect the sealing of the engine.

Joel
Retired Professor of Technology
Oxnard College

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Joel Rapose
Powerdynamo Importer USA
http://rapose.biz/

strichzwei
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Joined: 09/20/2012
Posts: 30
Thanks guys! S

Thanks guys!
S

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