I agree with @
InvisiBill 100% this is the fault of Kawasaki being lazy and/or cheap using the same bulb for both sides of the turn indicators.
I myself have done the relay itself, but I installed a resistor in each of front turn indicators. While this uses more wattage, it did fix the problem, and to be honest how long do you really keep the turn signal on.
To be honest I didn't know about the diodes and I'm going to he doing the diode modification soon, along with replacing the OEM turn indicator bulb with an LED to match the rest of my warning lights.
Finally my bike is 100% LEDs now!
The how-to article courtesy of our brothers over at ninja250.org
http://faq.ninja250.org/wiki/My_LED_...27t_work_right