1.5 mm Allen wrench
2 mm Allen wrench
21 mm socket set
Torque wrench (compatible with the 21mm socket; reads 55 in/lbs or 5 ft/lb)
Flat Blade screwdriver
7.5 weight suspension oil (Golden Spectro 125/150 (7.5w) is the stock oil. It's available for around $12.00 for 8 oz. at your local motorcycle shop)
Safety Glasses (I've had oil shoot out of the cartridge and into my eye!)
1) Remove ETA knob using a 2 mm Allen wrench (Note: my original plastic ETA knob broke, so I made a new one out of an old chain pin/plate) .
2) Remove the preload adjustment knobs from both sides using a 1.5mm Allen wrench.
3) Remove the black C-clips from both sides using a flat-blade screwdriver or similar.
4) Remove the top-caps using a 21mm socket. Be sure to clean any dirt away from the top-caps before removal, otherwise dirt could contaminate the oil cartridge inside the fork..
5) Removing the top caps will expose the ETA cartridge (and rebound cartridge, depending on the side that you are viewing).
6) Slowly compress the lower fork legs, which will expose the spring and spacer assemblies on both sides. Note the arrangement of the short spring/short spacer on the ETA side, and longer spring/ longer spacer on the rebound cartridge side (My fork is a 105mm travel model; 85mm travel forks may have a different spring/spacer arrangement). Remember the spring/spacer arrangement for reassembly later.
7) Unscrew the aluminum preload piece (it's a reverse thread, so turn it clockwise to loosen, instead of counter-clockwise). It's the silver piece that is sitting on top of the white plastic spacer, as indicated in the photo with the red arrows in the photo below.
8) Remove the spring, black plastic spacer, white plastic spacer, and aluminum preload piece. This exposes the rebound cartridge and ETA cartridges (the rods that are now visible sticking out of the top of the fork; actual guts of the cartridge are sitting down in the oil that you can see if you look down into the fork).
9) My fork is the 105mm model which uses two different length spring. (This spring came stock in my fork. It should be the "Heavy" springs, which according to Marzocchi are for riders between 180-220 lbs.) The spring for the ETA side is shown in the picture below. The length of the spring is 165mm. The small black PVC spacer is about 10mm long.
10) The spring that is in the rebound cartridge side is shown below (This spring came stock in my fork. It should be the "Heavy" springs, which according to Marzocchi are for riders between 180-220 lbs.). This is the longer of the two springs. The spring length is about 188mm. The longer black PVC spacer is about 55mm long.
11) If you are doing an oil change, at this point turn the fork upside down to drain all of the old oil. Cycle the cartridge rods in and out several times to empty the oil in the cartridges.
12) Turn the fork upright. With the springs still out, compress the lower fork legs completely and push the cartridge damping rods all the way down too. Fill the fork legs 1/2 full with oil. Turn the rebound adjustment screw fully clockwise (slowest rebound setting) and slowly cycle the cartridge damping rod in and out several times to fill the cartridges back up with oil (you can also turn the ETA lever to "compress" mode and cycle that rod to fill the ETA cartridge with oil). The cartridges are full when you no longer hear air cycling through the cartridges. (no picture available). The ETA cartridge will not engage correctly without cycling the air out of the cartridge and filling the oil to the proper height (see next step). I would even recommend cycling the lower legs (the gray colored part) up and down to fill the space between the lower stanchions and the legs - your oil bath. Once you are done cycling the lowers, slide the legs all of the way up to the crown (fully compress the legs).
13) Fill each of the fork legs with oil until the oil is between 55 and 45 mm from the top of the crown (the top of the inner threads inside the fork leg). See the tip below, for an easy way to measure oil height. The lower the oil height (55mm), the more "linear" feeling the fork becomes. If you are not achieving full travel, then try a lower oil height (but not below 55mm). If that doesn't work, then go to the next lightest weight spring set (or mix and match). To make the fork more "progressive" feeling raise the oil height closer to the 45mm height. This might be useful for heavier or more aggressive riders. (no picture available).
Tip: An easy way to measure the oil height is by using a straw; use a marker and draw a line near the middle of the straw. Now from this line, measure down toward one end 45, 50, & 55mm drawing a mark at each increment. Then, lower the straw down until the upper mark on your straw is even with the top of the fork crown's inner threads. Now, put your finger over the end of the straw and lift the straw out. The oil in the straw should be even with your desired height mark. Click on the picture below for a picture of the straw markings and a sample oil height..
14) Reinstall the springs, black PVC spacers, white spacers, and aluminum internal preload piece (reverse thread) in their appropriate sides.
15) Place the top-caps on top of the aluminum preload piece, and push it on until the small groove for the C-clip is exposed. (no picture)
16) Using a flat blade screwdriver, push the c-clip back into position.
17) Carefully thread the top-caps back into the crown making sure not to cross-thread the pieces. Torque the top-cap with a 21mm wrench to 55 in-lb (4.5 lb-ft) (no picture)
18) Reinstall the black preload adjustment knobs using a 1.5mm allen wrench.
19) Reinstall ETA lever with 2mm allen wrench.
20) At this point you're DONE! Go ride!
Important: I would highly recommend that you ride around the neighborhood cycling the fork up and down and then recheck your oil height. I have found that when I go back and recheck the height, it is significantly lower than what I had put in originally.
Standard Disclaimer: This site describes my experiences tuning and maintaining my suspension fork and this information is not an instruction manual. As always, use this information at your own risk. I am not in any way responsible for typos, misinformation, or any of your actions or results. Results may vary.