No African dunes but have ridden the sandy trails in the Nevada desert in the USA.
- Good knobbies are a must. Any street/road oriented tire will leave you frustrated and pushing the bike...the Bigs are heavy.
- Make certain she's full off high quality synthetic oil. Low speed, high rpm riding in warm temps will tax your engine cooling. Check oil level after EVERY ride cause the bike will use some.
- Have a way to adjust air pressure easily in the middle of the ride. Reduce for sand, increase for pavement and sand mixed with rocks.
Go for about 2mm of "Clean Rim" when messing with air pressures. But be careful of tire "creep" if you're not using rim-locks. Remove the nut from the valve stems so you can see the stem moving over at an angle first.....rather than tearing the stem off the tube.
- Make sure your bike is comfortable when standing up. Weight way to the rear - steer with your feet. Some guys find the rubber mounted pegs on the Bigs a problem here. You can temporarily defeat these with the creative use of a few washers and longer mounting bolts.
- Speed is your friend. Riding sand at 20kph will have you falling down alot.
- Cresting rises and dune tops at an angle is easier (at least at first) since it reduces the "Ohhhhhh Shit" factor when going down the other side
Expect to be a bit frustrated for the first 10 miles or so....then it's fun but don't get so carried away that you forget to watch cylinder head temp or any signs of overheating.
That's all I can think of