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One compression ring vs 2

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I am posting this here because it did not gain as many responses as I would have liked in the YZ/WR250F forum.

So, in my buildup, I am going to be installing a new Wiseco piston in my 250F. I have heard good things about both one and two comp ring pistons. My 2003 250F was running a OEM 2 ring up until now. I have the option to run either a one or two ring. I do a fair bit of track riding but more trail / play.

Would running a one ring (13.5:1) decrease reliability to much ? What would be the hour amount for new rings at least on a one comp ring piston compared to a two ringed piston? I have heard of the single ring pistons turning sideways in the cylinder, wreaking havoc on the head and cylinder. I am not all that concerned about it revving a tad slower than with a one ring piston.

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I would think that eliminating 1 ring would mean that it would wear out twice as fast. I'd run 2 rings, reliability is more important than performance to me.

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if your not biulding a "racing tool" go with the other brand that makes the 2 ring high comp piston. the name escapes me right now. i'm very happy with my wiseco 1 ring piston though :applause:

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one ring pistons, as i understand it, are more for racing where the piston/rings are replaced frequently. the reasoning behind it is you replace the ring before it wears enough to let to much compression through the ring end gap. the reason 2 ring pistons are more "durable" is the second ring in the 2 ring catches any blow by from the first ring. so basically, you will have higher compression longer with a 2 ring piston, even though the rings are wearing at the same rate. clear as mud?

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Alright. I'll send back the 2 one ringed pistons (don't ask) and get a 2 ringed one on order tomorrow. I have a choice of Wiseco or... well... Wiseco. Only company I can order from (middleman, not Wiseco) that has pistons for my bike.

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if you go to the wiseco website they have a lengthy tech article that explains the reason for 1 ring less weight shorter skirts etc... It all comes down the drag on the cylinder walls and the weight of the piston effects how much force is put on the rod. Ill try and find the link

Here it is, http://www.wiseco.com/Presentations/ForgedPistonTechnology.htm

and here is 1 from their forging department, haven't looked at it yet

http://www.wiseco.com/Presentations/WPF%20Presentation%20Master%202006%20Manual.htm

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