The stock bearing on my Buell was bi-directional even though it takes power in one direction. This is a highly recommended update. You can install it in a Sportster clutch without removing the primary cover. This would of course be easier. So if you need to switch to the primary version, it's worth making this upgrade. Otherwise, this can be done by simply removing the derby cover. IMPORTANT! Make sure you put it in the right direction or it will fall apart the first time you squeeze the clutch.