Nicholas: If you put "engine guard" in the search bar, you will come up with strings where we have discussed this before. When I searched this morning, the first string on the list had conversations confirming that there are folks on this forum that own 800 Drifters with 800 Classic Engine Guards on them. The shape and size of tube is different from the OEM accessory engine guard, but the 800 Classic Engine Guard fits. I even think I saw a part number. Good luck
The discussion also talks about other engine guards that fit the 800 drifter. The 800 Classic guard is probably the easiest to find and most reasonably priced. Also recommend you look at the forum photo galleries to see members bikes with engine guards installed so you have an idea of what is out there.