XJ750 Maxim fork seal removal. Very hard! Help!

I have been working on my own motorcycles for 20 years and somehow have always avoided having to replace the fork seals in the many UJMs I have owned over the years. Now, however, I find myself in possession of a 82 XJ750 Maxim with only 5500 miles (!) that is in need of a complete tune-up (all fluids and seals) and most of all, a fork seal replacement job. I have gotten to the point in the manual where it says to heat the outer part of the fork and then pull out the slider briskly to dislodge the seal. I have done this with much gusto but to no avail. The seal is still firmly seated. I went to YouTube and watched someone refill the fork with oil, replace the cap, and use a jack and hydraulic pressure to compress the fork to dislodge the seal. I have the tools for this but before I go using up a couple quarts of good oil, do you have any other thoughts?

 

Never mind. I dug into the archives and found some good ideas. Haven't done this "forum" thing before so I didn't know how to access past discussions.

 

Keep us posted! I'm going to work on seals this summer, I'm a total n00b.

These forums are a huge help, and welcome.

 

I just replaced my front fork seals yesterday, it was rather easy.

What I did:

1. Removed front brakes and tire assembly.
2. Drained the oil from the forks using the drain plug.
3. Found the correct fitting allen wrench that fits in the very bottom of the forks, below the drain plug.
4. Used my 1/2 impact gun, with reducers, to "rattle out" the bottom bolt. (The alternative is buying the damper removal tool, but a rattle gun works fast and easy)
5. I then removed the top assemblies, the top cap / spring, everything. I didn't need any special tools as my spring only popped up about an inch.
6. Replaced the seals using common sense, not to tear / rip them. Used a socket to seat the new seals. (oiled them also)
7. Assembly was a cinch. Slide the bottom part of the forks on and "rattle in" the bottom allen screw.
8. Replace drain screws, refill with 20w fork oil. 257cc to be exact.
9. Reassemble the top end.

I didn't take the forks completely off the bike. I used the center stand and since I have highway bars, just propped up a jack stand in the front.

 

***TIP***

No need to buy a damper removal tool. (You probably already own one and don't realize it.)

Most spark plug sockets have a hex cast onto the outside base of the socket.

Find one with a 19mm hex cast base.

Flip it over, and put it on your longest 3/8" drive extension. Clean out your toolbox of extensions, and make your new 19mm allen key as long as it needs to be to reach down inside the fork.

When finished, it comes apart and all the pieces go back to their "normal" functions.

 

Awesome tool tip Fitz...thanks!

 

Thanks, guys. This project has been fun as I haven't worked on Yamahas yet and they are a bit different from the Kawis and Hondas I usually ride.

Since I'm new to forums for info, I went to the archives and found some helpful hints that led me to a solution.

I ended up thinking outside the box and using a 3/4" hex head bolt (pretty darn close to 19mm), a 3/4" nut, and a 20" long piece of threaded rod to make my own damper removal tool. I used the nut to connect the rod to the bolt and tightened the crap out of the connection; I did not weld them together although that could be done. The nut kept the rod and bolt straight as well. I used a pair of vice grips to hold the top end of the rod and the correct 3/8"-drive hex socket in the bottom. Worked great and had both forks rebuilt in about an hour and a half.

Finished the rebuild last night, gassed it up, and took it for a ride. When it ran on all 4 cylinders, it was a hoot! Still need to check the valves, synch the carbs, and change the oil again (it was sitting for a long time before I got my hands on it).

Thanks again for the great information.

 

Don't forget to also check rear brake for delamination and I would also replace the front brake pads along with changing out the brake lines and rebuilding or replacing the master cylinder and rebuilding the caliper. You want to be able to stop and these 30 year old systems should not be relied on. Make it safe.

 

I rebuilt the entire front brake system since the bike had been seriously neglected by the previous owner(s). All new seals etc. I inspected the rear brake as suggested in a past post and it looked fine. Yeah, these old sleds are hard to stop if the brakes are not functioning 100%. My short test ride last night was a good shake down and the brakes performed well. I can't wait to really get out and ride!

 

so confused , i got the brakes disconnected,wheel and fender off oil drained and bottom allen bolt out. why the heck wont the bottom leg come off?

 

Because it's stopping against the seal/dust seal.

Since the front end is that far apart, loosen the bolts in the triple clamps and remove the fork assemblies.

Read and follow your service manual lest you damage something.

You have dust seals and retaining rings to remove before the seals will pop out. You need to know exactly what is what. If you don't have a manual, get one.

 

i forgot to mention it was a seca. with antidive system

and i got the top dust seal and the stupid ring clip under neath it out. and i cant get the tube off cuz there is a air valve that is like attached to the tube itself

 

just went to a friend's "friends" shop to use the air tools. but the cap wouldn't come off. they have never been serviced. we pulled the dust seal and clip. then took the damping bolt off the bottom and pulled it apart to replace the seals. took longer to refill because the bolt hole is so much smaller than the cap. but it worked out perfectly. i bought an upgraded set of seals and dust covers with reenforced spring on the dust caps to keep it closed better. total was $25 for seals and dust covers and another $10 a bottle of fork oil. i love Ebay for this old bike. and this forum so i can do it myself or with friends.

 

The air valve is only held on by the o-rings that seal it to the fork tube. If you twist the forks before pulling them down the o-rings will break free and make removal of the air valve assembly easier. There is also a thin ring below the air valve assembly that must be removed for the fork upper to slide out of the tree.

 

Yup i figured that out the hard way. Lol only cost me 1 bran new forkseal. the easiest way is to do it remove the fork leg. I got one done and calling it for the night, tomorow i will tackle the other.

 

It usually is.

Another tip*** Careful use of air tools for disassembly is fine; reassemble using hand tools only. Japanese alloy is like butter (or maybe tofu?)

 

My other bike has threaded fork caps. That has it's own special frustrations for reassembly. Right now I'm stuck in the fork seal replacement process on my Seca. How does one depress the fork cap and hold it down long enough to remove the retaining ring? Inquiring minds want to know.

*edit* I meant spring seat. The retaining rings are out but the spring seats don't come up any higher than where they were with the rings in.

 

I just changed oil a few days ago, and got good tricks from a few members on getting that cap out, in my bike topic. Hope it's useful to you, too.

 

While yo've got it apart get some new progressive springs from Chacal. You will be very glad you did!

 

The left one just decided to come out on it's own and rather politely did not roll somewhere hidden, dark and dusty. The right one needed a bit of slap and tickle.

 

foks, checked your thread. That is definitely the way to do it.

 

#$%@^#! my 3/8" drive hex does not fit through the hole in the bottom of the fork. I really dislike using keys.
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Buy a Six Point Socket.
Buy the correct Metric Allen Key.

Cut the Key to the Length you need to Fabricate a Special Tool.

 

Was leaning that way, thanks. Tomorrow...