Update: I bought two clutch baskets off ebay, and my suspicions were correct... Those bushings are supposed to be that way. It's not a crack, it's a slot put in there on purpose by the manufacturer. So, not being able to leave well enough alone, and since I now have a plethora of 550 clutch baskets, I took one of them apart. I pressed the bushings out for a better look: So, I'm not sure what I'm going to do at this point. All indications are that I've been chasing a non-problem this whole time, and I should simply get over it. Only reason I've invested any time in it to date is that (since I've owned this bike since new) I know that it did not used to sound that noisy. If it weren't for that, I'd be able to write it off easily. I think I'm going to put it back together with my original basket and get back to square one. In any event, I don't think anything is in grave danger of catastrophically failing, so maybe I'll mess with end play in the off season. Crap. I hate mysteries.