My recollection is that Harley even tried starting a racing class for that bike. Shame it didn't catch on.
Oh, there is (or at least, was) a whole club/class for it. Shelina Moreda races in it, though she's probably backed off now, with all the other stuff going on in her career.
The XR class is long gone from MotoAmerica and so is Shelina (she has some hard feelings toward the organization, for reasons I don't fully understand).
I still remember being at Indy when the XR1200s were racing as a MotoGP support class and I happened to pass a couple of volunteer corner workers, just as I heard one say to the other, "Have you had to pick up one of those Harleys yet? Those things are like tractors!" I guess that's a fair assessment after you've pulled a few Moto3 bikes out of the gravel trap.
I have a friend who has a low-mile XR1200. He actually owned a Sportster and had done hours of research on how he could modify it so it would perform a little better on the highway. He bought all the parts he needed on eBay and just needed to go to the Harley-Davidson dealer to buy a gasket, last item on the list. He walked in and there was a pristine XR1200 with 93 miles on it that some guy "had bought for his wife." My friend thought, hmm, I could do a lot of work and still not have something that performs as good as this or I could just trade in my Sportster for this. He ended up selling those parts back to eBay.