Reply to thread

Message: [QUOTE="motometal, post: 431991, member: 24727"] Certainly the amount of ring seating needed would vary widely depending on the mismatch in profile between the rings and the cylinder. For example, I just changed out the original top end in my CR250. It had about 1 1/2 seasons on it. I'm not going to guess at the hours, because you guys will yell at me. The compression was at 190, and measuring the old and new pistons side by side I had trouble finding any wear on the old piston (using a good digital micrometer). The ring gap on the old rings was about .002" wider than the new ones. Certainly most of this is normal wear rather than seating, but let's say for argument's sake 1/2 of this wear took place before the ring conformed to the cylinder, which puts us at .001" difference in circumference. Mathematically, since circumference = dia. x pi, this would equate to a difference in diameter of only 1/3.14 (about one third) of the difference in circumference, or about .00035". This puts us at .00017" per side. I would venture a guess that this amount of gap, or mismatch would not result in any significant loss in compression...in fact the film of oil would effectively seal a gap larger than that. My point? I think machining and quality control practices have produced engines that require minimal ring seating. Certainly, there are engines out there on the loose end of the tolerance that would require more break in and seating, thus furthering the need for carefull break in and good cross hatch on the cylinder. Regarding the finish on chrome fork tubes...if these imperfections or scratches carry oil, why doesn't the fork tube act like a dust magnet?I would think that some of these dust particles would then be carried back into the fork, then washed off by the oil. The oil would become dirty very quickly. [/QUOTE]

Verification: Which ocean is California closest to?