Join Date: Mar 2015
Location: Los Angeles Area
I think this is difficult to do just by calculating compared to the combined length of the stock spring and spacer.
Drop the new spring into the fork tube and fully extend the tube.
Slide in a piece of PVC (1" sch40 or sch80) which is longer than you need and sticks up out of the fork tube.
Mark the PVC where it meets the top of the tube.
Remove the PVC
Next, measure on the fork cap the distance from where the cap seals at the top of the tube to the bottom of the cap where it will meet the PVC. Mmake sure the cap is set to the middle of the preload adjustment (second line).
Mark the PVC to shorten it by that distance.
Now add back the preload distance (20mm sounds like too much, but that may be correct).
Cut the PVC at that point.
You should now have a spacer that, once the cap is back on, compresses the spring by your preload distance.
Does this make sense?
2012 DL650A (purchased Dec 2017)
2005 DRZ400S (sold Dec 2017)
1972 Norton Commando (sold 1984)
1978 Suzuki DR370 (sold 1982)
Last edited by KSM; 03-06-2018 at 12:49 PM.