Well, as one American to another (won't vouch for any of this for any other nationalities):

Customs agents in one or more countries (can't remember which ones now - Chile was one I believe) asked for the bike title. They seemed to know the difference between the title and the registration. So, if you run into one of these types, then you may have a problem if you don't have the title. I'd suggest you contact the lien holder and try to get permission, in some sort of letter of release.

A CARNET IS NOT NEEDED IN SOUTH AMERICA, although some countries would appear to have it, in writing, as a requirement. Its just the folks at the border/points of entry can be persuaded they are wrong. I was asked about it when crossing from Colombia into Ecuador. Ecuador seems to be the one country this comes up the most, but when asked I just said I didn't have it, and it never came up in conversation again, and I didn't have a problem getting the temp import doc on the bike.

No one I have met traveling in CA/SA HAS HAD TO PRODUCE A CARNET!

I've not had to provide an IDP in CA/SA, but I haven't been to Brazil yet (or a few other countries). I've showed it when asking for my drivers license - so far they've all sort of looked at it and gone "huh?" and where much more happy when I showed them a good copy of my state issued drivers license. However, it just makes sense to spend the few dollars required to get it and carry it.

As to "normal insurance" (what's that?):

AS FAR AS I KNOW, there is no US vehicle insurer that covers your motorcycle or car once you cross into Mexico. You get insurance from the countries you travel through - there is no policy you can get covers you for all of CA and SA. And probably can't get (or afford) comprehensive coverage - damage on your bike, theft, fire, etc. You are only buying 3rd party liability coverage - protection for when you hit someone or something.

I've been asked twice at Argentine border crossings for the insurance on my bike - that's insurance from an Argentine issuer. No other time in SA. In CA (Mexico), its required, and a couple other CA countries, but where it is, its sold at the border crossing. If you get into a country without it, it may still be "legally" required. But I can't tell you about that - I just kept my insurance situation in mind when riding. And again, since many CA/SA countries follow Napoleanic law instead of English law, then you are guilty until proven otherwise - carrying liability insurance is usually your get out of jail card should the worst happen.

Once again, what seems to be official requirements and what's practiced are different, so no one can really give a good answer - sort of depends on whose asking, what they know about US documents (usually little) and the specific situation.

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quastdog
Chiang Mai, Thailand