Fork seals 81 kz 550

Hey I was wondering if someone can give me a run down on changing the fork seals on my 81 kz550 ltd with the air assist forks, thanks

You should get a manual as it will have service data, such as fork oil specs & fork free spring length, that sort of thing.

Usually, the hardest thing is removing the bottom allen bolts. An air impact wrench is probably the best/easiest way - use a hardened 8mm socket or brake caliper socket. A cheap tool may twist or bugger the bolt head. I guess it would be best to use the air tool while the forks are on the bike - the weight of the bike will provide spring pressure to the inner cylinders. You could apply heat to the allen bolts first using a propane torch, but you should probably remove the top plugs first & dump out the old oil before heating (forks removed from bike)..

The top fork plug circlips can be hard to remove as well if you've never done it before.
The plugs can be stuck from grunge & an old hardened o-ring.

Relieve the air pressure first.
Remove the circlips by pressing down on the fork plugs then remove the circlips.
You may need a helper & keep in mind that the plugs will be under spring pressure.
Some guys use some sort of tool - I think from the auto parts store.
Dump the oil into a suitable container without dumping out the parts. Pour in some solvent, temporarily plug the opening, invert a few times, then dump that out. It's a messy job, hence the solvent rinse. I used lacquer thinner the last time.
Remove the allen bolts, then everything should come apart.
FYI: the allen bolts are screwed into damper rods (inner cylinders). If the allen bolts spin without coming out, then you're going to have to lower a tool down inside the tubes to keep the damper rods from spinning, then unscrew the allen bolts.
Some guys use a big ole screwdriver to pry out the seals, but I use an off-the-shelf seal puller from the auto parts store. If you've never pulled a seal before, note that there is a metal ring encased within the fork seals: when pulling the seals, be sure to hook the metal ring. I do the job at the end of a work table & use a small scrap of wood to protect the fork tubes.
To drive the seals 1-1/2" pvc pipe & fittings work fine. I used an old good seal as a protector when driving the new... probably not necessary, but that's what I did.

ADMIN: I don't know if you can combine this thread with same one in the chassis forum, but there is a duplicate there too.


You can get several manuals in my signature. You should probably download all of them.