Evolution engines make a lot of noise inside the rocker cover. This is due to the way H-D designed the rocker arm installation. The bolt that locks the rocker shaft is not a tight fit at all; when installed it allows the rocker shaft to rotate slightly forward and backwards in the housing. There it hits the rocker shaft bolt; which provides you with the unnecessary clicking sound. This kit comes with 4 precision tapered bushings that fit around the rocker shaft bolts when it is installed; which eliminates rocker shaft movement. It does not interfere with the working of the rocker arm. The kit includes a washer and nut for installation and the required tool for aligning the rocker arm shaft correctly; before the bushing is installed. An experienced mechanic should be able to get the bike back on the road in around 3 hours. Note: When the rocker shafts require removal a new Rocker Locker kit will be required.