Well, I made it to Lima. Lot's more adventures today: freezing my ass off, more bike problems (nothing to do with sprockets or chains), and some more outright bribery of Peruvians.
By the way, the front sprocket isn't as loose as it may have seemed; the chain on the other hand just refuses to stay tight! I'll be hunting for a new chain tomorrow. I have a 14 tooth front sprocket to swap out with the old one and I know a guy who's flying to Peru in a few days who is going to bring me a new XRR 15 tooth front.
I'm going to go eat some dinner. I'll update later tonight. Cheers!