I have a 1988 CR250 and am uncertain as to whether it has a chrome cylinder bore or not. I took the cylinder to a mechanic at a Honda shop, and he said he couldn't tell by looking at it. It is a problem because I have new rings for it that have instructions stating that they must not be used with a chrome cylinder bore. The cylinder is original and the serial number on the frame is JH2ME0309 JM004001. Is there any way to tell from the serial number if this motorcycle was equipped with a chrome cylinder bore?