I was in the primary to swap my front pulley and primary chain tensioner so I figered while I was in there I'd put in the Baker bearing. I got the race off and saw that the mainshaft has a big gash in it. I figure someone had already changed the bearing and the cut the old race off but had cut in to the mainshaft as well. I tried the Baker anyway but the gash made the primary leak without the race to cover it. Had to open it back up and put replacements for the OEM bearing in. Someday I'm going to have to replace the mainshaft and put in the Baker bearing.