I have a 2003 FXSTDI Deuce and I note it has a dual shock system under the frame for the rear. This is comprised of two Showa adjustable shocks. The book shows how to adjust them but doesn't say how much to adjust. Right now this bike rides like a lumber wagon and I'd like to soften it up a bit. So how much should a guy turn them for a starting point? I weigh 180 pounds and when sitting on the bike I get about a half inch of compression right now

 

On my Deluxe I needed to adjust out for more pre-load for two up riding. I only had to adjust it one throw of the spanner wrench. You are limited by the frame on low much you can turn the wrench. One throw for me was about one half turn. It sounds like you need to adjust the opposite to soften the pre-load. Other than getting under the bike it is pretty simple. Good luck.

 

Go to www.fatbillscustoms.com. He has a how to adjust shocks section there.

 

I just gain and lose weight as necessary to make the shocks feel right.

 

LOL......have no problem gaining the weight.....just can't loose it anymore.

 

Look aft of where the shocks attach at the forward end. You will see a 1-1/8" retention nut at the forward end of the shock body and probably 4 threads showing forward of the retention nut. That means that the shocks are already set to their softest setting.
HD sends the Softails out with the shocks set to the softest setting and most owner's never change the setting. I do change my setting depending on if I am riding solo or two up. If you don't see the 4 threads, then the shocks have been set firmer.
The hardest part of setting them is the first time you have to break loose the retention nut. HD uses loctite on it, so it may require using a heat gun or hair dryer on the nut to loosen the loctite. Once you have the retention nut loose and backed off, you will need a spanner wrench to turn the shock body. HD sells them for less then $10. Turn each shock fully the same direction until they stop. Paint a thin white stripe running forward/aft on the bottom of each shock body. This way you will know how many full turns you make with each shock as you adjust them. Make sure both shocks are equally adjusted. If you adjust the shocks fully one way or the other, back off just a hair when you are done. This way they wont be hard to adjust next time. There is no reason to loctite the retention nut. I barely snug it tight and it has never loosened, between adjustments.
It takes me less then 5 minutes to adjust the shocks, it is just the first time that is time consuming.
Good luck,
Tom