This is one major job that requires the front of the bike to be partially disassembled and requires some 100$ in parts. Maybe more or less depending on where you get yours from!
You will need the new seals and the bottom drain screw rings which have a rubber gasket on the inside diameter of it. You should also replace the dust boots while you are in there as well.
Also make sure that your bike is SECURELY standing or sitting on whatever you are using.. mine slid down with the front tire removed and I had to call in for assistance from work to lift her back up!
It is a good idea to soak the top in rust remover of your choice (I prefer Aerokroil) and then later after reassembly coat the top layer with bearing grease so it doesnt rust back up!
You could also push down on the top cap and remove the ring that holds it in at this time but that would result in making a big mess. You can save this step for later on]]
Get your bike onto its centerstand or come up with your own way or raising the front end off the ground
remove the front axle
pull her out and take off the brake caliper and support it hanging from a metal rod or something to release stress onto the brake lines (clothes hanger works awesome) remove the front fender…
Now if you get lucky like I did the lower front fender screws will be so tight and rusted that they break off like mine and someone elses on this board. have a tap and die set ready and new bolts!
loosen up the upper bolts on the triple clamp (2) and then the upper one near the black dust cap at the handle bar.. do one site at a time. the forks should now slide out unless you have inspection stickers, parking permits and other stuff stuck to it.. I had to get brand new everything for mine.
the forks should be now out, after you had loosened up the screws and or removed any stickers
bike should look like this
the forks had less fluid than specified. one had 450ml and the other one 460ml… 480ml are required and I went with 10W
also while you have the top cap removed, replace the O-ring that's on it and clean the grooves etc. Its a #10 O-Ring
remove the dust boot by taking a small flat screwdriver and slightly prying up on certain spots. this will raise the dust seal off from its seating and pull it out towards the top. Now if you are going to reuse it, make sure that the inner lips are greased with the specified grease!
with the dust boot removed another clip will have to be removed, use your small screwdriver or dentists hooks ( i love these things) to pull the clip out of its groove on one side and then push around in a circle and the whole thing will come out.
once the clip is removed pull very hard on the fork and hold the fork tube in your hands to pull the seal out of its seating. or use the wise again to your advantage.
remember how everything was sitting together. the seal will have to be installed with its writing facing upward
the bottom part of the fork
new 10W fork oil from Bel Ray
stick you finger into the oil and apply some grease to the inner lip of the new seal and the outer lip of the fork tube.. it will make assembly aka pressing the seal in very easy, now you could use some pvc pipe or just a rounded non sharp object to push the seal into its position.. use some lubrication!
an O-ring set found on my garage
put everything back in the reverse order…
However: Make sure that when you have the fork apart to CLEAN everything inside and out.. You dont want clean oil in there with dirt still in it, also inspect all your Teflon bushings for wear. Also if you fork has some pitting in it from rust or items hitting it, a new seal wont make any difference and it does get torn up by uneven surfaces.
Before you put the fork in, bounce the whole thing out by pushing up and down on the fork when installed inside the fork tube. Once the forks are back installed into the bike push down several time and see if everything is equally! You should also place the forks next to each other after they had been cleaned and refilled to see if they have the same height.
If you just want to change the fork oil while one the bike; follow this procedure:
Remove top black cap from the front forks
Raise your bike so the front wheel is off the ground and can be removed
Push down on the silver cap in order to remove the clip holding it down inside the fork (the ones which were under the black caps)
remove the front wheel now
inside the front fork tubes is a drain bolt that is hidden very good. Its a hex bolt that can only be reached with the wheel and axle removed
remove the bolt (you should also replace those since they have a built in rubber gasket)
the fork oil should now drain
get some cheap oil and flush out dirt from the top with the cheap oil first before refilling with fork oil
reinstall the drain bolts
fill each fork with 470ml of fork oil
assemble everything in the reverse order!