It is a 97 so not as vintage as yours. I picked this up last summer. It was pretty neglected and mice were homesteading in its airbox also. Seller said it wouldn't shift - just 1st and neutral. I showed him the bent the shift lever and pulled it back out so it didn't bang against the bottom of the cases. It shifted fine and we kept the same price.
I found a new front wheel, rear brake assembly, and $5.00 front fender on Ebay and ordered sprockets, chain, filters and some misc stuff from Rocky Mountain. RM had a sale on numbers so I ordered them and botched the installation.
After spreading it all over the garage, cleaning, greasing, and getting it back together (not a small accomplishment for me), it is a pure blast for a total investment of under $700.00
XRs are slow but billy goat trail bikes and I have explored lots of trails at Saddleback East in Kentucky.
I'd say keep it and if you want to come explore the 600 acres of trails at Saddleback with me, just let me know.
http://saddlebackeast.org/
Saddleback is hosting a couple of races during the 2016 Kentuckiana series so I expect them to improve one of the MX tracks on the property.