Don't know of a substitute for the "Genuine Kawasaki Part," garthw; I somehow thought the size was peculiar to the KLR (or maybe including other Kawasaki bikes/ATVs).
160 degrees F. is the nominal opening temperature, but . . . the Thermo-Bob boys have no problem with a 195-degree F. thermostat.
Thus, if your thermostat works around that temperature, and your coolant doesn't boil, I think you can get by with the old part for awhile. As long as the temperature gauge needle stays out of the red block at the far right of the scale, I think you're operating within safe temperature limits.
Wouldn't hesitate to run the old thermostat under those conditions 'til I could get a replacement, myself, but--your call! With a pressurizing radiator cap, circulating water pump, and an operating fan, I think you'll be o.k., for awhile.
(BTW, Clymer cautions against running without a thermostat.)
Last edited by Damocles; 07-13-2013 at 08:13 PM.