Hey Sean Hilbert,
You said you went through several designs before settling on a certain one, What design did you go with and what material??
As far as the expense versus gain, I've read they last twice as long. I've found one place that had the sizes and could ship them next day for $51 a piece. you can get stock bearing set with seals for about $50. so it's going to be a little over twice as much but they last twice as long. So, it will actally save money ( having to tear down engine an replace gaskets, etc.) I guess the only other thing you would have to worry about is the main bearing outlasting the bottom end bearing. Who makes the best Bottom end bearing for 125's???
This is the e-mail I got from bearing works (a cr 125 uses the same size as My rm125)
We do sell alot of this size in ceramic hybrids. Pretty popular for karts. These can outlast your standard ones, but the main benefit is that they accelerate faster and generate less heat. Your fuel mix wont effect the bearings. All the materials are compatible. As far as the rotating mass of piston/rod effecting these, no problem. If they were entirely ceramic, there might be a problem with fracturing from the shock, mismounting, or thermal expansion of your crank and/or case. These are made of steel rings, ceramic balls and thermoplastic cage (400F).