Road King is Touring frame and so is the FXR, it just has a small front end. Dyna and Softail are different.

 

The FXR frame is quite different than a touring frame. It doesn't have the extended neck for the inverted triple trees, it has additional crossmembers for rigidity, and the only thing they have in common is the triangle in the rear section of the frame. They are not interchangeable.

 

Thanks everyone…..we’re probably going to do the 34t pulley. Tearing into the primary is not a big deal, just messy. Moral of the story, even though the bikes are very similar and within two years…..never assume parts interchange.