They are called Rotopax. I bought them on ebay when the Kiwi was strong on the USD. You can buy seconds with only cosmetic issues. I bought the brackets and spin-lock system too. Not cheap but very well made and good for the purpose.
I bought the bike as a project, stripped it down with @
cambo and wirebrushed and painted the whole thing back up. For a bike that cost me $500 to buy and turned over with new fuel, I've spend $2000 doing it up. Needed new transfer case, new bearings all round, front CV joints, middle drive shaft, new swing arm boot, new wet and dry clutch, and nearly completely re-wired and new tires. Won't buy a yamaha again, hard to get parts for. Honda the way to go. But at least I know it off by heart. The brakes aren't the best on these old yams either. Getting brake fade on a hilly station descent is pretty scary, but at least it has a low ratio box.