2013 RMZ Spring SFF Preload adjuster issue

Hi Guys, I have just gone and collected myself a very tidy 2013 RMZ450! Been a few years since I have had a bike. Anyway, I went to set the clickers on the forks to the factory settings as I am not sure where the previous owner set them and I can not get the preload adjuster on the top of the right fork to move at all. I don't want to force anything so I thought I would ask and see if anybody has had a similar issue or has a tip. Cheers!