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post #1 of 3 (permalink) Old 11-29-2019, 07:33 AM Thread Starter
:::Mini LT50 Rider:::
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Join Date: Oct 2019
Posts: 56

What does everyone run their ring gaps at? (For 94mm bbk, preferably a CP piston, that’s what I have..)

I called cp and they said 18 thousands top ring, and 26 or 27 bottom ring.... .018 is the minimum by my calculations...

Just wondering what everyone is running.. I’m .018 1st, and .026 2nd.... just hoping I didn’t gap too much or too little, since they’re new rings... I trusted cp with the numbers plus my calculations,..... just need to know I’m right, or some numbers that everyone else is running or seems to work better. So I know if I’m around the right area
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post #2 of 3 (permalink) Old 11-29-2019, 07:42 AM Thread Starter
:::Mini LT50 Rider:::
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Join Date: Oct 2019
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One other thing.... which ring goes where? Idk if anyone known what they were doing with this engine before hand.. they had (what I’ve read) the top ring on the second slot, and the 2nd (with the slight shaving around the outside of the ring) on the top .... I put my new ones in the same way and filed them the same way...

Didn’t know if that’s how CP sent them there’s or the previous owner just mixed them up like that.. it smoked pretty bad before, maybe this had something to do with it??? But they were definitely out of spec before... both well past .020.... I think the second was like .030 something
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post #3 of 3 (permalink) Old 11-30-2019, 01:17 AM
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I hate that they give super generalized settings, because they apply to a car, not an all aluminium, nikasil plated motorcycle/atv. The way you have set them will work, but they're way wider than they need to be.

The specs they gave are way wider than I use. I use 0.003" per inch of bore as the absolute minimum. So the bore is basically 3.7" 3.7 x 0.003" is barely over 0.011" So I'd go with 0.012" to be safe. This is for the Top ring only. (The shiny one)

The second ring (black ring) (some pistons don't have one) add 0.004"-0.006" to the gap of the first ring. This is to ensure that it doesn't trap pressure between the rings, because that invites ring flutter. The second ring is an oil scraper. It's not responsible for compression.

The minimum on the oil rails is 0.015" and I don't bother checking them anymore. They're always in safe territory.

The top ring is the shiny one. Also look for any markings, and make sure they're up.
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