I would definately lean towards the smaller bikes, a 200 -250cc. The main reason here is the fuel economy. Most will give you about 400km from 12 liters of fuel.
This weekend I had decided to have a breakfast at the southern most tip of Africa, Cape Agulhas. Took the new toy TZR250 stroker, filled up in Cape Town and I was on the road. Little did I know that the reserve tap does not work. So there I was standing next to the road 10 km from destination - hungry.
Only 210km on a 15 liter tank. Does anyone want to buy a cheap 250? Hope she didn't hear that.

The other consideration for me would be speed. You don't want to be constantly worrying about the trucks killing you while they are overtaking you. Here they are allowed to drive 100km per hour. So the bike needs to do a little more than that to be safer. Most 125cc will do about 100kmph and the 200cc will do 120kmph (4 strokes). As stated earlier by others, once off-road you no longer need to worry about speed as much.

The main thing with touring would be to get yourself and the bike back home again in one piece. Here reliablity, easy parts, economy, comfort come into play.

There are many capable small bikes out there.

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To those who say it can't be done - stand aside for those who are already doing it.

Oh Dear. My 500cc Enfield fails again, it will only do 384 Km on 12 litres of fuel
but good points here and in edteamsirs post.

Interesting Thread.

I'm planning to go around Africa on my 200cc dual-purpose bike and the first thing every non-biker tells me is "it can't be done on a 200cc, you need a bigger bike". My reasons for taking my Skygo GY6 200cc are as follows:

1. less expensive bike - carnet and insurance is cheap. (Bike was R14 000 brand new)
2. parts availability - throughout Africa parts are available (uses universal parts)
3. mechanically simple - use basic knowledge, and if you can't you'll easily find someone who can fix it.
4. Max carry weight is 140kg, I weight 65kg so that leaves more than enough space for luggage.
5. Fully loaded(tent, 10L fuel, 5L water, and all other stuff) I can still go 100km/h comfortable, dropping to 80 on hills. Off-road isn't a problem either.
6. Fuel economy - I get about 30km per liter, so with a 12L tank its 350km minimum, combined with the 10L extra fuel its more that 600km without a petrol station. That's more than enough for me.
7. Safety - Easy to pick up bike or get out of difficult terrain. Your less of a target going through Africa on a small bike.


Only downside for me is the speed, its sucks only being able to go 100 on tar and having big truck going past you (luckily there are back roads, made specially for me). So far I'm very happy with the 200cc, but I see myself riding a KLR650 in the future.

Well, that's just my opinion and ride whatever keeps you smiling.

Safe riding all
Rassie

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He who lives the adventurous life will remain unafraid when he finds himself alone - Raymond B. Fosdick