Insurance!
For Africa and most of South America, you are buying liability insurance (not comprehensive, i.e., collision, theft, fire, etc.) just to keep your ass out of jail should the unthinkable happen - you hit something, someone.
Read the policy!
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You don't get a policy! - just a piece of paper to show the cops. Nowhere do you see coverage limits, details of what, when, where and how. Just a phone number to call. Anyone ever called the number on their Comesa card (the yellow card insurance you get in Africa)? Did they help?
US companies aren't going to cover stuff happening in Central/South America. They have no control, no handle on the situation. No way to inspect damage, determine cause (police report?!
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). Why would they ever pay out anything?
I'm sure similar for European insurance. Insuring you and your bike for stuff happening a continent away. No way, Jose!
So, you get it at the borders, when required. Otherwise, you don't waste time looking for it. There's roads to ride, places to go, people to see. Too much to do, too little time - and you want to waste your time buying insurance?
Don't worry! Be happy! and remember, having to pay for insurance you pray to god you never need is simply putting your money in the pocket of someone else, with no likely benefit to be received.
Which is why you'd be stupid to take a really expensive bike to one of them countries. If you aren't prepared to just leave it - just walk away - then you aren't prepared to go there.