I have never been convinced of the practicality/need for a roller bearing.
In my opinin, nothing wrong with the stock bronze oilite bushing...it could take a beating and handle dust and dirt.
Correct me if I'm wrong here....but doesn't the roller bearing setup install in the flywheel, not the crank recess ?
If so, that puts the roller bearing much closer to the output shaft bearing (307/308), and then there is not much room for the input shaft to have any wiggle room...so to speak.
So...what I am suggesting here, is that those little rollers are taking up a lot of load, from your output shaft, and they are in a dirty environment.
Bronze anyone ?