Biglry are you sure the OEM F6B bearings are round? It was my belief they are roller bearing themselves referred to as needle by some. Not everyone thinks the All Balls are an upgrade to the more expensive OEM. Just recently changed out the neck bearing on a Yamaha Venture with 120K on the odo and the stock bearings were roller just like the aftermarket replacements I put in. I do know one thing I will not use any Chinese made bearings.