So I picked up some used forks. Accordinh to previous owner it had an extra spacer for preload. Took off fork cap and took out the extra spacer. After reinstalling and tightening up the cap, now I can't adjust for preload. Any suggestions?
Do you know if the springs have been changed out with aftermarket springs?
When you removed these short spacers, did the forks drop in height equal to the short spacers removed?
I'm thinking possibly that the forks springs may have been changed out, but with shorter springs than OEM, and the spacers are making up the difference in length rather than a longer custom spacer made or obtained.
Is the OEM spacer still inside?
The OEM SP2 spring length is 244mm and the SP1 fork spring is 250mm.
Then you're trying to add preload with the shorter springs and the adjuster plate is bottomed out against the stopper ring at the bottom of the fork cap. That's why it won't budge anymore.
You'll need to check the current spring length to verify this.
The adjust case lock nut is not tightened so it loosens when the adjust case is rotated.