I am rebuilding my engine and I picked up a matching donor engine that just had a cracked off part near the side cover. It has the same codes for bearings as my old cases. I took those bearings and the crankshaft out and put them in mine, but when I go to tighten it down, it starts to seize up. It turned over freely by hand in the old cases and the bearings are the right ones, so not sure what could be wrong. It did spin the old bearings, which is why they're being replaced along with the crankshaft.

 

Even thought you save the bearings had the same codes, is the crankshaft itself right? Also is this with the top end together as well that you are trying to spin it?

 

Bearings are sized to the crank, they came with that crank and the case codes are identical, so it would have identical cases and journals. That's not what it is. I had it in at my shop today and they saw there's a little bit of deformity on the corners of where the bearings go, so I'm going to try a very slight chamfer for now on his advice.