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Hey folks. Got new piston and rings for my sons kymco mongoose 250. manual says to install with mark up. Ok the mark on the rings is a R and a RN, which one goes were? Any help would be greatly appreciated. Thanks in advance for any help.

I had some leaky seals and a bad running Polaris 250 2x4 mod W937527.Compression was 90 lbs.Just had the cylinder to a shop for measuring.Standard 72mm is 2.835 inches this cylinder is round and measures 2.839 and a bit wider at the bottom.The ring gap with the used rings is .25. Here is my question>The piston has the ring stops that pin,Can I use the standard piston with a ring set .10 over? The manual says ring gap seated in the cylinder should be .0009 to .0018. I am disabled and it will only run me 800 ft to a mailbox once a day and maybe a little use around the yard,so a bore,and new parts are out fixed income cant afford that. Can I go .010 over on the rings with the standard piston? Thanks for any advice

Hello fellow members, I recently tore down my grandsons 1995 250 Polaris Trail Boss to replace the rings. Problem is, its been bored over and now mics at 72.60 at the top, and 72.54 at the bottom. I only honed the cylinder to remove the glaze. What size over piston and rings do you think I should use?

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