Hello; I want to recommend Brazil as a motorcycle travel destination. It was the highlight of my trip through 15 countries in Latin America. You can easily ship your bike by air to or from São Paulo with Augusto Leocadio,
motoshipco@gmail.com +55 11 9.8152.4142. I found him through the HUBB.
I live on Vancouver Island and shipped my bike from São Paulo to Seattle with Augusto and can say that he knows the shipping business, is very professional and pays attention to details. My bike arrived without a scratch, with all my riding and camping gear, clothes and other stuff in my boxes. The bike was secured in a steel framed box which I'm keeping for future shipping.
Also, Augusto is associated with Touratech Brazil which has a great shop in a nice, safe area of São Paulo plus another one in Joinville. Gabriel Colafemina (gabriel@touratech.com.br) is the owner and he has great people working there, André and Stephano. All these people became good friends of mine. I left my bike with them in full confidence. They also have scheduled tours organized by BMW Rider Experience.
Brazil is a fantastic country with a huge variety of roads, including amazing mountain twisties, my favorites. The food is great, there is lots of campgrounds or hostels to stay at, the beaches and brazilian beauties are legendary but best of all, you will meet the warmest, friendliest, most helpful people and will be invited to stay at their homes, meet their families and friends, eat at their table. They are the nicest people I have met anywhere.
In conclusion I would say; don't stop in Buenos Aires, go to Brazil! You can ship your bike to or from there with Augusto. If that doesn't work, maybe you can rent or you can join a tour with Gabriel. They're trying to develop their business and I know they will do their very best to help you.