Googled how-to
Softail Shock Adjustment:
1) Jack the bike up so the rear tire is off the ground. The more clearance you have the easier it is. Don't forget to strap the bike down. You don't want it falling on you while you’re wrenching underneath it.
2) Loosen the jam nut all the way out. It’s a 1 1/16" nut. If it doesn't want to loosen easily (which is often the case), soak it in some penetrating lube. The spanner wrench mentioned in step 3 is also a 1 1/16" wrench.
3) With a spanner wrench (HD p/n 94448-82B) turn the adjuster plate counter-clockwise (so the shock housing moves towards the front of the bike) until it’s up against the jam nut.
4) Then take a light colored paint pen, or a piece of duct tape, and mark the 6 o'clock position on the adjuster plate to use as a reference point when doing your adjustment. Don't worry if they're not in exactly the same position on both shocks. That’s normal.
Now you’re ready to adjust the shocks to your weight/load.
5) With the spanner wrench, turn the adjuster plate clockwise no more than 4 complete turns by counting how many times the mark from step 4 crosses the 6 o'clock position. 0 turns is the stiffest setting, and 4 turns is the softest setting.
6) While holding the adjuster plate in place with the spanner wrench, tighten the jam nut up against the adjuster plate by turning the nut clockwise.
7) Now repeat the exact same process on the other shock. The key is to adjust both shocks equally.
The general rule of thumb I use is: 4 turns for load <= 180 lbs.
3 turns for 180lbs < load <= 235lbs 2 turns for 235lbs < load <= 300lbs 1 turn for 300lbs < load <= 375lbs 0 turns for 375 < load
Examples:
235lbs solo rider: 3 full turns
235lbs solo rider + 32lbs pack: 2.5 turns
235lbs rider + 150lbs passenger + 32lbs pack: 0.5 turns