Originally Posted by
Brandon Melton
but keep in mind that a ceramic rear bearing is also a key factor in the upgrades that the VR doesn't have.
By the time you buy a crank, p/s/r, and a bearing, you might as well just buy a new engine because it's probably going to be nearly as much. There comes a point where rebuilds just aren't worth it. Just food for thought, but I know in these times everybody's trying to maximize value.
Changing the piston and sleeve is ok but I never invest more on a worn out engine.
This might be a good idea to keep the 121VR as spare engine and buy a 121VR-ST for racing. That's what I plan to do myself.