Yes, I agree. Check this link
That will direct you straight to the motorcycle listings in South Africa, just make sure to check the top right hand corner of the page to select the city/province.
You can make use of the search bar to put in the model name. I would suggest that you try and browse every brand and model of bikes you are interested in, to see what is available, before you decide to buy one. Gumtree's got everything....
Have fun buying your steed.