Here's a Spal pdf document that Danno posted back in 2005. It shows a drawing of the radiator fan used for the VRSC.
The VRSC fans used by HD are Spal "pull" type. For the early models (2002 & 2003) the fans used where Spal P/N VA31-A101-46 A. In 2004 HD changed these to a special dual fan unit = Spal P/N 2VA58-A101-46A. This dual unit is only available to HD.
The fan diameter for both versions is 130 mm = 5.118".