Describing the procedure in words is a little difficult, but basically you are going to tighten the spokes on the side of the displaced portion of the rim. Look closely at how the wheel is built. You will see how tightening the spokes on one side will pull the wheel to that side and visa versa.
Word of warning....make changes in very small increments. 1/4 turn at a time, max. You will need to set up some way to measure the runout. A trueing stand is best, but most of us don't have that option. I've used the axle in a stand, or even on the bike holding a stationary pointer to pick up the runout. Give it a try, just take your time and think out each move. If you have any buddies in the bicycle world, they are often adept at wheel trueing, as it is a normal part of life for them.
Thanks JTT, you wouldn't want to be my mechanic?:confused: You seem to know alot about biking. Did you race? I know your a Ref, here. Do you still ride?
back to the truing thing... I was thinking that if you leave the rim on the bike and set up a guide to measure the runout that this would work. If I recall correctly.... When you find a spot that is out, go to the opposite side of that and tighten the three - four spokes and measure again.
As for me, I come from a Roadracing background, and only raced MX for a couple of years (but have been around it for well over 10 yrs). I still ride MX regularly, but now just for fun. I ride mainly with Roddy MacLeod #409 Pro. Sorry, I have barely enough time to keep my bike running, and help Roddy whenever possible. If I can ever be of help, drop me a line.