The elusive Turbo Rumble Bee made for a 1998 Harley event in Tucson, Arizona. This model has specially designed side caps and body colors of orange and black made exclusively for the event. A hard-to-find model nowadays (2017), it has the same guts as a regular ProYo Turbo Bee.
There are other side cap designs of this same model. One has "Rumble Bee" on the side cap that shows the bee and motocycle from the side. On this particular model it says, "www.proyo.com" instead. There are also versions of the side cap from an earlier year that has the event date on it.
This model was available only at the Harley event and at the brick-and-mortar ProYo Museum in Tucson, Arizona.