Article by ErirZ of the XLFORUM®: ¹⁾

• The washer that separates the feed from the scavenge gerotors on 2007 style Buell oil pumps can freely rotate and wear against the inside bore of the pump. The pump bore is not grooved but can be worn in from the washer spinning during use. It does slowly introduce aluminum into the oil supply and return but very slowly and the oil filter should take care of any problematic debris. Also, the piston jets do not have a check valve. They are free flowing.
• On the 2005 pump, the OD of the scavenge gerotor is smaller than the feed gerotor.
• The OD is the same on the feed and scavenge gerotors on the 2007 pump. ²⁾

2007 Buell XB oil pump (# 26357-02B) with a groove that was worn into the bore after ~7k miles of use 3)

2005 Buell XB oil pump showing one of the two keys that prevent the separating washer from rotating. 4)

Here are the two pumps, 2007 on left and 2005 on right. 5)

Both pumps shown with their respective separating plates. 6)

Note: Since the XL Oil Pump (26204-91A (new style)) is the same oil pump as the 2007 later Buell Oil Pump (26357-02B), the same issues listed here should be expected.