Poor man Denny
Welcome to the forums!
For 5k, you're stretching it to find a 1000 cc or above bike! At least not one that's working.
In Sharjah, the used bike market is near the Cricket Stadium. There are about a dozen of so dealers that get used bikes from Japan and sell there. You'll probably get the best deals here, but you need to know what to get and how to check if the bike will work and get 'passed'. Many of these bikes have not been started for months.
For over 1000 cc, you'll probably need to 'order' those, as they normally keep bikes upto 400-600 cc that move faster in the market.
Let us know your report of the area, once you're there! Personally not been there for a while