Just for some insight into what goes on with the con rod bearing here is a good write up that explains it way better than I could at a technical shop school........
Excessive RPM. Big end bearings can fail in minutes if subjected to excessive RPM. The reason is: During regular operation the rollers (in the big end bearing) roll on the outside surface of the crankshaft journal and on the inside surface of the connecting rod. A light film of mix oil coats the bearings with every rotation the crankshaft makes. This bath of oil (and fuel) lubricates the bearing, which removes friction and keeps the bearing running cool. When the engine is subjected to excessive RPM (like limbing with the throttle wide open), the rollers roll as fast as they can and then start "skating." This skating or sliding activity scrapes away the cushion of oil on the bearing surfaces. The bearing gets hot instantly. If the engine speed does not come down to where the rollers can roll again, it fails quickly. Even if the speed returns to normal, the bearing sustains some damage.
Keep the RPM's down , I usually go 500 below saw spec to allow for fluctuations from conditions that can change the setting .
But what is the threshold for excessive RPM in a modern saw? There was a crowd here years ago that swore up and down that running a saw over 14k would result in "slinging the oil off the crank and bearings and burning up the saw immediately." However, some of the saw builders here routinely run their work saws at 16-17k and the saws are having long service lives. As oil products and metal components in the engines continue to improve, I would think the allowable RPM threshold would continue to climb.