I made mention of the Yamaha Tenere earlier, as it continues to show up as I research used bikes in Brasil. I'm rather fond of it and it seems like a strong candidate for the trip.
This is from a Bikeexif post:
"In the late 70s, ‘dual sport’ or ‘enduro’ style bikes with long-range fuel tanks were starting to attract attention in Europe. In Japan, Yamaha took notice. In 1981, they started work on a production version of the motorcycles racing in events such as the Paris Dakar. The first Yamaha Ténéré appeared for the 1983 model year, and was promoted as a new kind of all-round touring motorcycle—a machine that was able to tackle any terrain, was simple to maintain, and was sold at an affordable price. Within ten years, 61,000 Ténérés had been sold in Europe, including over 20,000 in France. Yamaha’s excellent Design Café website has the full history of this iconic machine, along with some terrific period photography. The Ténéré shown above is the first model, which retains a certain gawky charm even today, a quarter of a century later. The front disc brake was an innovation for time, along with the long-travel rear swingarm, and the top speed was 160 kph—not bad for a 595 cc bike with only 43 bhp and 30 liters of fuel to lug around. Those yellow fork gaiters still look funky, don’t you think?"