I assume the bearing you installed had ceramic balls. Is this correct?
Ceramic bearings, allthough extremely hard, are extremely fragile. Any impact to the bearing can cause the balls to crack, split, or shatter. So if this bearing was subject to impact of any sort (ie. hammering into the crankcase, or even falling off the workbench) this would be the cause of the failure. Extreme care MUST be used when handling these special bearings, and if there is any doubt that the new bearing has been subject to impact it MUST be discarded and replaced.
The proper method of installation of ceramic bearings is critical to avoid such problems.
The best method is to heat the crankcase to roughly 250 deg. F. and refrigerate the bearings prior to installation. Then simply drop the bearings in place. They should slip right in to their final position in the crankcase easily. This technique does require some skill that the bearing is not accidentially allowed to slip in crooked, if it is it can get stuck. This will require the bearing to be PRESSED back out and recooled for another try. IN NO CASE SHOULD YOU HAMMER THESE BEARINGS IN OR OUT OF THE CRANKCASE!
The next best method would be to use a pulling tool to draw the bearing into positin in the crankcase. This is quite easy but does require some special tools. These tools are available from Novarossi and other sources.
The last method I would reccomend, but as a last resort is using a press. The only downfall tho this method is the possibility to push the bearing in a little crooked and the race can actually gouge the bearing surface in the crankcase. This can build up a slight amount of material from the crankase behind the bearing race and not allow it to seat completely. Also the bearing can be off axis if this happens causing running or performance issues.
Good luck on the next engine, and remember to treat ceramic bearings with the utmost care when handling and installing. They are a great product but must be dealt with carefully.
Originally Posted by ViperSkull
I have no idea how this happened. I did look at my engine bearings and one of the balls in the main bearing looks like it has split in half so that might have caused it. I'm so annoyed as this piston is only 3 race meetings old and the bearings are 1 race meeting old.