Kawasaki calls it a "Stay" and the Kawasaki Part Number is 35011-1327
Search eBay and Google for the Part Number. They can be found new and used for ~$30.00 +/-
Also, FWIW take a look at the Air Filter Housing Vent that is in your picture (It's the white plastic round/cone shaped thing). It looks like you're missing the plug that should be in the hose that is on the bottom of it. If this hose is not plugged when riding the bike, it'll be sucking unfiltered road/track dirt and debris coming off the rear tire, into the engine, completely bypassing the Air Filter.
Last edited by Bluehighways; 03-27-2018 at 03:10 AM.