Thought I should comment on this one, because I just finished riding north through Sudan yesterday.
Yes, it is absolutely unbearably hot in Egypt / Sudan at this time of year, but it is still possible to ride, providing you time your day properly. My themometer hit 55 degs for a couple of hours in the Sudanese desert at a time during the middle of the day. The trick is to leave at dawn, ride until 11 or so, rest during the hottest part of the day, and then ride in the late afternoon from about 5 until sunset. Doing this you could do about 200 - 250 kms a day on the tracks south of Wadi Halfa, and up to 400kms on the tar south of Abu Dom.
There are two routes you can take south once you enter Sudan. The better route for a solo unsupported motorbike is the Nile route, via Dongola and then the tarred road from Abu Dom to Khartoum, although you do miss the famous Meroe pyramids this way. If you push this, you can do it in three days, however four or five would be more comfortable.
The only section of this route where water is not available is from Wadi Halfa heading towards Akasha, where it is about 75kms to the first truck stop. After this unfiltered Nile water is readily available, although bottled water is only available in the towns, such as Abri and Dongola. I found I was drinking close to ten litres of water a day and still not having to piss.
The other route, through the desert via the train line has good water at Station 6, however I really don't think you could possibly carry enough water on a solo motorbike to make this feasible at this time of year.
The route down the Nile is mainly heavily corrugated track, with a mixture of stony / sandy tracks. There are very few real sand streches on this road, but you can always head off the track if you feel the urge. Fuel is available in Abri from jerry cans and at a petrol station in Kerma (60kms north of Dongola), thus meaning your range will only need to be about 300kms.
Also be aware that the distances on the Michelin map between Wadi Halfa and Abri are wrong. From Halfa - Akasha is 125kms, and then another 55kms to Abri, not 115kms as on the Michelin map.
Sudanese hospitality is fantastic, and you can easily stay and eat for free in any of the villages along the route, where you will be plied with a bed, food (fuul/beans) and water. It is a "dry" country, so make sure you have plenty of

s before leaving Aswan.
cheers
Matt Roach
[This message has been edited by Matt Roach (edited 29 July 2005).]