I been cycling twice for 2 years through Africa. If you need contacts, feel free to contact me.
No particular brand to be recommended.
I recommend not to look on weight, when choosing your bike, rather durability.
Don't take low-rider front racks! They are difficult in sand for the bags tend to bump on the sand. Same applies for narrow jungle tracks.
Don't travel with a railer!
Always carry loads of hose clems for basic, rough repairs.
Carry 10 L MSR water bags!