Originally Posted by SR
Or instead of looking for a battery, just get the bike to a motorcycle shop. They will know what to do and make something work.
This. Or at the very least get the old battery to a moto shop. Trying to order over the phone is just asking for trouble no matter how well you speak Spanish.
Don't miss the mummy museum, and try your best to do some exploring in the hills east and south of town. Lots of dirt roads and tracks up there (although watch out for mining trucks on the main routes).