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black z400

JE piston installation: Ring order

15 posts in this topic

I'm putting a JE 13.5:1 piston in my bike, and it has no instructions. The piston has 3 ring rails but only a compression ring, and 2 oil rings and the spacer. Am I missing a compression ring? I assume I'm correct in this just going by the stock configuration. Does it matter which ring goes on top and bottom of the oil ring?

If anybody has a good link to ring installation, I'd appreciate it.

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I just ran to my garage and the JE piston I have has 2 grooves for rings not 3?

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If you have that piston out of the bike, can you snap a pic of it for me? All the paperwork I have says CRF on it, but it also seems to have way deeper valve recessions then stock. It's confusing the hell out of me. I may be wrong though. I can stick my fingernail in 3 grooves, but one the middle one is definately less deep, and I feel its probably not a ring groove. If you could just verify the little indentation, thats my mistake.

Thanks alot.

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I see the same three rails as this guy, I put the oil rings in the lower deep rail and the compression ring in the upper deep rail. I left the middle rail open, it's not very deep anyway. Is this correct?

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I see the same three rails as this guy, I put the oil rings in the lower deep rail and the compression ring in the upper deep rail. I left the middle rail open, it's not very deep anyway. Is this correct?

Yes. that is correct

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No confusion really,you couldn't get any rings in that so called middle rail anyway its way to shallow,at least on the 3 we have installed.

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That's very correct, it is a shallow rail. Just wondering why it's there and why the installation instructions never mentioned it. Like I read somewhere in this forum, my JE instructions said something about installing on a Subaru.

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What your seeing is the accumulator groove, see picture.. This is a two ringer but your single ring has the same groove...

Quote JE piston info... An accumulator groove is machined into the land between the top and second ring. It provides additional volume where residual combustion gases that have "blown by" the top ring can collect. This additional volume helps to reduce pressure between the top & second ring, thus aiding in top ring seal and minimizing ring flutter.

accumulator.jpg

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Well thanks Brad_Aus, this was a question that's been hanging around since last year. Then all of a sudden I run into the same predicament, thanks everybody for your support.

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I'm putting a JE 13.5:1 piston in my bike, and it has no instructions. The piston has 3 ring rails but only a compression ring, and 2 oil rings and the spacer. Am I missing a compression ring? I assume I'm correct in this just going by the stock configuration. Does it matter which ring goes on top and bottom of the oil ring?

If anybody has a good link to ring installation, I'd appreciate it.

Also make sure if there are any makings on the ring (ie a letter close to the ring end gap)that they face UPWARDS

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Well I forget what company rings I got with my JE piston but I couldn't find any markings on the compression ring and I didn't think I saw a bevel edge either. Should I go back in and pull that ring to double check or take a chance it's right? Will the OEM rings fit a JE 13.5:1 piston?

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