PERFORMANCE SPARK PLUG KAWASAKI&nbsp;KZ550-F&nbsp;(1984-1983) * 1037yBR12ZC1037yz 1. Higher HP and torque by up to 3 % 2. increased economy by up to 5% 3. 360 Firing Technology 4. Improved acceleration by up to 15 % 5. 25,000 miles - 40,000 km duration