MikesYR1 Posted January 8, 2015 Share Posted January 8, 2015 I have to bore out my cylinders and I'm having trouble figuring out what the STD size is for the cylinders! My current piston tops show 6 82 Its odd because they typical go 6 25 or 6 50 or 6 75 if there Over sized by .25 .50 .75 I want to go .50 OS BUT idk if they're already .82 OS but that makes no sense to me and to get a custom made piston and rings would be way to much for this lil bike so i doubt anyone did that. Any help mates? Link to comment Share on other sites More sharing options...
blackhat250 Posted January 8, 2015 Share Posted January 8, 2015 Yip mike, go Wiseco , they make pistons up to 2.00 over size, lots in USA, have a browse and see, Forged pistons and are very hard waring Look - in USA, 60.96 http://www.ebay.co.uk/itm/NOS-Yamaha-YR1-60-96mm-pistons-2-/111213147190?pt=Motorcycles_Parts_Accessories&hash=item19e4d1f436 Link to comment Share on other sites More sharing options...
fabiostar Posted January 26, 2015 Share Posted January 26, 2015 wiseco is the way..great pistons Link to comment Share on other sites More sharing options...
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