Leaderboard

The 0.003" taper means the lip at the top will be 0.003" also. That will break a new ring. I don't think your measurements are quite accurate though because the standard bore should be bigger than your worn measurement. If your measures are right, then it seems that the piston to bore clearance is right at the wear limit(though we can exceed that and still get a reliable engine), but if the standard bore is slightly bigger as the book says, then there is a bit more piston clearance than they recommend for a guaranteed good engine. I could get that running though, and not needing any oil between services probably If it was me, for myself or for a customer, if they were agreeable, check the crank, I'd take the ridge off, check the piston to ring clearance, then fit a set of rings with a barrel base gasket, head gasket, and valve grind and seals. It would go for years, but only because I'd take care to minimise the ring gap and bed it in carefully. If the piston was worn and needed to be replaced, I'd bore it. An engine with taper makes the rings work harder to maintain a seal, they have to expand and contract every stroke, so if they get overheated, or don't bed in, then they'll let oil past.. If the rings are bedded in carefully in the first ten minutes after first start, and don't ever get overheated, then it'll be a perfectly good engine. We can generally wear our two pistons before we need to do the crank.. It's like Gw says, you could get it to go again, but it's not going to last as long as a rebore, especially if the work and care riding aren't all they should be.