Tony, no idea what else to use, but this "cover' is listed as "bolt" in the "frame" section of the parts look-up.
They call it "bolt" and part number is
92153-0474
2014 Kawasaki NINJA 1000 ABS (ZX1000MEF) Frame | Babbitts Kawasaki Parts House
I think this one will work, based on Kawasaki's parts look-up and fitment chart.
http://www.oppracing.com/product_display/5276-lightech-steering-stem-head-nut-m28-x-10/
They call it "bolt" and part number is
92153-0474
2014 Kawasaki NINJA 1000 ABS (ZX1000MEF) Frame | Babbitts Kawasaki Parts House
I think this one will work, based on Kawasaki's parts look-up and fitment chart.
http://www.oppracing.com/product_display/5276-lightech-steering-stem-head-nut-m28-x-10/