Tips on Changing Fork Seals

I'm about the change the seals on my 85 ZX750. I note in the manual a special tool is required to separate the forks, of course I don't have the tool. Any tips on separating the forks.

There are some really good topics on this of you do a forum search on changing fork seals. they even have images and what you can use to make your own "special" tools so you don't have to buy some expensive one you'll only use once or twice.

I did the search and most of the links are dead but did find one that has good pics. Someone mentioned removing the lower allen bolt while the forks are still installed on the bike, the triple tree acts as a vice holding the upper fork tube: anyone tried this?

Nope, never tried that stunt, but it sounds like a great idea.

I did that but the bolt just stayed in and spun itself. It will work, I just wish I had a drill I quickly spin it out, so I just took off the forks, drained the fluid and kept flushing the oil(time spent) and I used a flat screw driver and hammered down on one side on theoil seal causing it to pop up, but try leaving the forks in the trees and it will help.

"Any tips on separating the forks."


I've had good results on two KZs using an air powered impact driver. On my KZ1300 it failed thoroughly. actually I was able to get the lower fork tube off with the impact driver. I just couldn't get it to tighten back up. I suggest that you beg or borrow an air powered impact driver and keep in mind that it's the acceleration that does the work. Many quick starts are what does the work, NOT spinning the whole assembly at full speed.

Once I had it apart I was able to really see what was needed to grip the damper rod without damage for reassembly.

KZCSI

Post edited by: KZCSI, at: 2007/07/17 21:03

gaillarry wrote:

I did the search and most of the links are dead but did find one that has good pics. Someone mentioned removing the lower allen bolt while the forks are still installed on the bike, the triple tree acts as a vice holding the upper fork tube: anyone tried this?

The upper fork tube isn't what spins, it's the damper rod at the bottom.

A wooden broom handle really does work well if you have to use hand tools. Pull the cap and spring out, taper the end of a wooden broom handle so it's pointy, and jam it down in there and it will grab the damper rod.

Best bet though is just to hit the 6mm allen bolt with an air impact gun and it will come out. Don't forget circlip pliers for the circlip above the seal. Then grab the tube in one hand and the slider in the other and start slamming them apart. 3 good whacks and they'll seperate.

For my 550, I found that 1 1/2 inch pvc pipe is exactly the right size to drive the new seal in. 4 bucks at your home depot or lowes or whatever. I think the 750 is the same size.

Also it helps to have spring pressure on the fork when removing the allen bolt, so the way I do it is first loosen, but do not remove the top cap of the fork, then remove the entire fork leg from the motorcycle, then use an inpact driver on the allen, then after it's off remove the top cap and spring. Assembly usually goes without a hitch with an impact driver, but if the bolt wont tighten you can install the spring and cap, then the spring pressure *should* keep the damper from spinning enough to tighten it with the impact driver. If you don't have an impact driver I suggest not attempting the job because you won't be successful.

why take the forks apart?, get an old scewdriver and sharpen it to a point then pierce the old seal and pull it out then replace it with the new one. 10 minute job. got this trick off a mate.

myelr21 wrote:

why take the forks apart?, get an old scewdriver and sharpen it to a point then pierce the old seal and pull it out then replace it with the new one. 10 minute job. got this trick off a mate.

You can change the fork seals with out taking the forks apart? Please tell.:ohmy:

In order to change the seal without disassembling the fork you must still remove the fork from the bike. Disconnect the speedometer drive, remove the brake calipers, loosen the triple trees and slide the forks and front wheel off as a unit.
There's a wire retainer that holds the seal into the fork slider. Remove the retainer and, very carefully drill a small hole into the top of the seal. 3/32" is good. Now use an appropriate size sheetmatal screw and run it in to the hole a thread or two. Grip the screw with a pliers and pull out the seal.

I prefer to leave the fork tubes on the bike and disassemble the forks from the bottom, but I suppose the other method does avoid messing with the springs.

Good Luck

KZCSI

Post edited by: KZCSI, at: 2007/07/21 10:29

KZCSI wrote:

In order to change the seal without disassembling the fork you must still remove the fork from the bike. Disconnect the speedometer drive, remove the brake calipers, loosen the triple trees and slide the forks and front wheel off as a unit.
There's a wire retainer that holds the seal into the fork slider. Remove the retainer and, very carefully drill a small hole into the top of the seal. 3/32" is good. Now use an appropriate size sheetmatal screw and run it in to the hole a thread or two. Grip the screw with a pliers and pull out the seal.

I prefer to leave the fork tubes on the bike and disassemble the forks from the bottom, but I suppose the other method does avoid messing with the springs.

Good Luck

KZCSI<br><br>Post edited by: KZCSI, at: 2007/07/21 10:29

I think these methods without disassembling the legs are mostly urban legend. This method, the screwdriver thing mentioned earlier, as well as the use of compressed air to blow the seal out that's been mentioned before. In a perfect world with no corrosion on a brand new bike maybe, but on a 30 yr old motorcycle? I'd have to see it because those seals are dang difficult to get out most the time even after disassembly using a seal puller. I'd like to here from anyone that's ever sucessfully used these alternate methods before. We've all read about how great these can work. Anyone actually done it? With the fork still assembled on the motorcycle, the seal would have to come straight out up the leg since the leg keeps it from cocking. You guys think it's feasable to pull the entire outer edge of a seal straight out using a screw and vise grips? I don't but would be interested in hearing.