I did this repair on a 68 Bultaco. This was before I had any large shop equipment. I had a supplier bore the engine case out about 3mm larger first. Then I machined up a steel sleeve that was a slight press into the case. The bore was sized so the bearing fit was correct after installation. It was tricky getting the tolerance perfect, but it turned out well. I rode that bike for years, sold it to my brother, he later sold it to one of his friends.
The material used for the sleeve is not important. It can be steel, stainless, brass or aluminum. The usual method is to: bore the case out; warm the case and press in the insert; let it cool then finish bore the insert to size. This is all done in the same setup, but you need a lathe and mill available at the same time.
If the bearing "just" spins (meaning the slightest of free fits), you could loctite the OD to hold it in the cases. It really depends on the amount of play. While not recommended, I've seen bores carefully centerpunched in even rows to raise the metal enough so the bearing is located. The "space" is filled with red loctite.
Most engine cases temperatures are around 200-225*F, so the locitite will hold. It usually takes about 300-325*F to break the bond.
__________________
2011 EC250E
|