You get more life from a double ring piston. The compression is what seals the ring to the cylinder wall, causing it to wear. When the top ring wears too much, the compression bypasses it and seals the second ring.

I have Wiseco single ring pistons in my overbore, and they work great. Use a top-notch oil in good quantity, and that can greatly enhance your ring and cylinder life.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
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