I don't know why people think that they are going to lose so much weight from wheels. Yes there is a weight loss and some more than others but not as much as you guys think.
Remember, compare weights with wheels fully loaded ie; rotors, bearings/seals, hub, sprocket and same tires. The weight loss is not as much as you think. I have checked weights on a lot of aftermarket wheels through the years. Currently I use Carrozerria Forged Aluminum wheels which saved me a total of 9 3/4lbs compared to stock.....fully outfitted as described above. Dymag Carbon Fiber wheels(rare) will save an additional 3lbs. BSTs are probably around the same or a little better.
I've seen the GSXR 1k wheels only about 4-5lbs. If the R1 wheels are lighter, I doubt not by more than 4lbs my guess.
As you change to aluminum sprockets, lightweight brake rotors and titanium rotor bolts then you can see another 3lbs+ from all that.
On my old Kawasaki 750 Turbo, I went from the old 18" wheels to modern 17" wheels from a Kawi ZX6 rear and a Honda 16" front wheel and saved 16lbs from everything.......rotors, tires, etc........trust me the old 18" whees are super heavy.....
FYI, my Busa weighs 490lbs with a full tank of fuel and still using a modded stock exhaust. I weigh everything down to the ounce.