It's not really easy to rent in Cairo, there was a place ages ago, but not now. Someone to do with Franco Pica (Dakar Racer) had some Yamaha TT's for awhile, but I've heard nothing for ages... and not in Cairo now so hard to check.
One option is the KTM place in sharm el sheikh (search and you may find it), but they're not cheap and driving around the Sinaii is more than a little tricky at the moment I think.
Sorry... another option may be to see if anyone in the Cairo community would rent to you for a couple of weeks. My brother is there and has my old bike... he might be interested... PM me and I'll ask him.