adjusting rear shock preload on 620

[sbrguy]

i have a stock 620 with stock shock, i see that there are there rings underneath the spring for adjusting preload.

question is what tools do i need to add more preload as i have put a top case on the bike and you can definitely tell that even when empty it is adding about 10-15lbs to the back of the bike so that i squats more.

also how many turns do you do of the rings for each 10lbs of added weight?

is there a technique you need to do, such as tighten the rings one after another in other words just adjust one and then back it up with the second ring, or do you tighten the rings against each other?

[Howie]

One ring tightens against the other to lock it in place.  Loosen the nut on top, Tighten the bottom nut until proper sag is set.  Someone else will have to post the sag spec.  Tighten top nut against bottom nut you are done.  There are special spanner wrenches for the chore like this one here
http://www.motostrano.com/ohshspwr.html
A hammer punch or screwdriver, depending on how many rules you are willing to break.  Expect to mar the nuts.