Motorcycle Repair: 1984 FXR, fork tubes, fork oil

Question
Hey Mike, I've got a 1984 FXR-SP frame w/ a 91' motor in it. My front end is very mushy and I want to cure that. I'm told by the seller that it's a Sportster dual disc front end. How can I I.D. these forks to determine the correct amount of fork oil and the correct progressive rate replacement springs? Thanks!

Answer
Measure the upper fork tubes and that will tell you what forks you have. If they are sportster tubes they will be 35MM forks. If the front end is mushy then you can drain the oil and put a heavier fork oil in and that will help.
Good luck and happy riding
Mike