Nothing serious, but I rode South Africa to Kenya and later Morocco to Guinea Bissau, on a beat up classic Vespa PX200E... not exactly reliable, not exactly fuel efficient, not exactly environmentally friendly, and not exactly suitable... but still capable, even offroad.
Still, single cylindered two strokes are great - especially for their simplicity and ease of repair and service.
My biggest concern with two stroke engines is oil consumption. You think gasoline can be difficult to get in some places, try to find two stroke oil! Of course it exists, but finding the holy grail might be easier. And as for synthetic or even semi synthetic... ha, ha, ha.
With your regular 2% oil mixture, and pluss minus 5L fuel per 100km (heavy loaded old tech single cylindered two stoke bikes with small engines are usually thirsty), cutting the shortest distance across Africa translates into 12 liters or so of two stroke oil... that is if no oil is spilled, you don't mix too much, no bottles are broken or lost, and no detours are taken, and no idling with wheels not rolling. In all reality, the oil consumption would likely be more like 15 liters. So, if you plan to go through the heart of Africa and don't want to spend much time searching for oil, be prepared to carry many liters of oil at all time!
Some places, digging for it might actually be easiest.