Using your K&N replacement air filter is easy. First, locate the stock air filter on your Kawasaki ZX6R Ninja. Remove the old filter carefully, making sure not to let any debris fall into the air intake. Then, place the new K&N filter in the same position as the old one and secure it properly. For maintenance, it's recommended to clean the filter every 10,000 - 15,000 miles, depending on your riding conditions. If you often ride in dusty or dirty environments, you may need to clean it more frequently. When cleaning, use a K&N filter cleaning kit. Follow the instructions on the kit to ensure proper cleaning and re - oiling. This will keep your filter in top shape and your engine running smoothly. Also, always check the filter for any signs of damage before and after cleaning. If there are tears or holes, replace the filter immediately.