Bought a used '03 YZ450F recently. Did the 1st oil change today. When I went to change the oil filter I found that the previous owner had installed a stainless oil filter. It has KN-142 on the side of it. Is this a K&N filter? Do they make oil filters? Do the YZs do OK with these? How do you clean these? Can I use Simple Green, carb cleaner, kerosene? Any help would be appreciated.