Re: V4 - Rebuild question
This has been a much debated subject but heres the jist of it --<br /><br />Yes, you can oversize one cylinder in a 2 stroke outboard. OE pistons and quality (not all) aftermarket pistons are all within weight tolerences whether they are standard or oversize.<br /><br />The true issue is wear on the cylinders. Cylinders are measured with a dial bore gauge for size, taper and out-of-round. Each cylinder is measured in at least 4 places. <br /><br />The final measurements are taken to determine the "finished bore size". This is the cylinder size, at room temp, that the new ring will run aginist. Not the measurement of the cylinder before its honed. <br /><br />Run or wear tolerences are not the same as rebuild specs. Rebuild specs are not the same as remanufacturing or manufacturing specs. Manufacturing specs are not the same as blueprinting specs.<br /><br />Each cylinder has a life cycle measured in thousandths of an inch. Each time a hone passes through a cylinder, it removes metal which is wear.<br /><br />The dial bore gauge is what will determine what gets bored. Not what the cylinder looks like or what the piston looks like. <br /><br />Running quality -- if the cylinders are within spec, the motor will run perfectly whether its all bored the same or not. We've run, many times, a race motor that all but one cylinder cleaned up at .020. The other cylinder was taken to .030 or .040. The motors all turned the same rpm and ran the same speed at over 8000 rpm. And no, the motors were not blueprinted -- class rules did not allow that. They were built with "as produced" parts.
