I've been dreading this job, mainly because, when I read the manual and see the pictures showing various "special" tools, I get the urge to make my own, but wonder IF I'll be able to get them right.
Also, I've never worked on USD forks, so it's ALL new.
I started by getting a 10mm x 1.0 nut, and 2 pieces of 1/2" copper tube at the hardware store, and soldered (that's RIGHT - with lead!) the 10mm nut to the end of one to, I hoped, make the damper-tube holding tool I'd need. I then lifted both ends of 'Big Red' and got the windshield, both side fairings and the fender off. Next I removed the brake caliper bolts and bungeed the calipers up and out of the way, then removed the wheel.
The right fork was the first to work on as I figured it would be the more complex one, and off it came. Following the manual I loosened off the top cap, then measured the width of the damper tube (.394") followed by measuring to find the nearest sized bit ABOVE that number - 13/32". I then took a piece of 1/8" aluminum which had about a 30 degree bend lengthwise for strength, and drilled a 13/32 hole about 3/4" in from one side, making my "fork spring compressor" tool. Then I marked a SLIGHTLY WIDENING set of lines to connect the hole to the side and cut it out, de-burring as I went along. With my wife's help, I pulled down on the spacer till she had room to push my new tool in and under the nut holding the top aluminum plug. Now I had an idea of what I'd need to make to make for a "fork spring stopper", as I could then see that the damper rod is "waisted" just below the nut. By luck (
) my aluminum compressor fit HIGHER than the waist so I measured that as being .340" and found that an 11/32 bit was just slightly wider.
I then took a piece of 1/16" stainless steel and drilled the 11/32 hole, joined it by PARALLEL lines to the edge which I cut out, making my "stopper". Again my wife stepped in, and while I held the spring down further by inserting a small screwdriver thru holes in the spacer and pushing (HARD!) till there was space above the compressor tool so she could insert my NEW tool. EUREKA - IT WORKED!!!
Now it was easy to remove the cap with damping-rod attached, attach my copper-and-nut tool to the damper-tube threaded part, push down on the screwdriver till I released BOTH the "compressor" and "stopper", and release the spring.
Draining the fork oil surprised me - it looked pretty good - without an odour, considering there are 31,000 miles on it, so I continued as per the manual, measured in the correct amount, 'burped' the air out (be careful if you make a damper tube holder like I did, as oil comes UP thru it when you push it down for burping), then basically reversed all the above steps with aid of my wife, and re-installed that fork leg. TOTAL time from start to that point, INCLUDING making the 2 tools, was THREE hours!
The left leg with no damping rod, took only 35 minutes from on-the-bike to on-the-bike, torqued and ready. The re-installation of wheel, calipers, plastic bits took a while longer, but I would say it's NOT a job the average guy can't do, especially if you make your tools before you start (check my pictures).
Now for picture explanations:
#1 is a diagram of what the fork damper-tube looks like, and its measurements;
#2 is a picture of the 3 tools I made, with a tape for scale (the "stopper" can be as small as 1 1/2" wide, rather than long as mine);
#3 is a close-up of the damper-tube and nut held by the compressor and stopper - NOTE the waist;
#4 is with damper-tube holder attached;
#5 is after the oil was added, and the cap and damper rod are being attached (note the screwdriver I used for pushing down on the springs); and
#6 is a shot of Big Red just before I started re-installing the right leg.