In my opinion, no they are not especially on these motors. The K&N filters tend not to seal well in the stock air box and let dirt through. Some may have better success with the K&N cone-type filters. I never liked cleaning mine and then waiting for it to dry and then re-oiling it (plus the cost of the oil and cleaner). Many folks here will recommend the TYMAR intake for about $120 or so. The filter are simply replaced for about $25 and they last for a good while with better filtering and airflow. I run a homemade version that uses the same filter as the TYMAR (Donaldson filter), but if I was doing it over I'd just get the TYMAR. Cheers!