Topic: 836cc Big bore piston rings issue

[archie2133]

Im doing a top end build and measured my bore and found it is 65mm (836cc) big bore. I bought some new piston rings and measured the end gap of the ring when I fit it into the cylinder.

The gap is 0.144 in. (3.6mm). The work shop manual states that the standard piston ring gap should be no greater than 0.028in. (0.7mm).

The picture attached shows the the cylinder on the left which has the one I bought and the cylinder on the right is the one I removed from my piston.

As you can see visibly the gap is quite different. Anyone know what's gone wrong here?

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[disco]

What's the ring gap on the original ring? Is it within the serviceable limit of 0.7mm?

If you have measured the bore at 65mm (with a digital caliber or whatever) I'd say it looks like you've been supplied a set of wrongly labelled rings.

[archie2133]

The original gap is within spec.

The only issue is that I've removed all.of them from the pistons and there is no marking telling me which way is up.

Im starting to think that also.

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[69cb750]

Anyone know what's gone wrong here?

Yes, you have the wrong rings

[Phoenix]

I have a crusin image 836 kit.  If that is what you are using, the rings can go either side up as reported to me by Cruzin.  As far as the gap, there is a big difference between forged and cast pistons according to Honda man.  Most of the shops wanted to do .020 whereas whereas HM suggested about .010.  Don't take my word for it,  I'm just say to check it.  And for God's sake don't be an idiot like me and gap the oil ring spacer.