Fork seal question(s).

I bought a 1983 Seca XJ900 last summer, it runs strong, but has minor head leak. I had some minor electrical issues, which have mostly been resolved due to the help I received here. So thanks everyone.

It has sat for a few months and now I'm ready to get it back out. Before I garaged it I notice that the right side fork seal is/was leaking fluid. I have talked to several people about the issue and the advice seems to be that I should just take it somewhere and have a proper MC repair shop fix it.

I have moderate ability when it comes to repair, but limited tools. So... should I take it in or is the repair easy enough that I can take care of it myself?

Any help is appreciated.

 

A) where are you located?

B) get a manual for the bike so you dont do what my P.O. did with my900R. he tried to do the seals himself (it would appear) and he damaged some internal parts made of Unobtanium. im trying to get the parts made now but i dont know that ill be successful...

C) make sure the MC shop is a WELL REPUTED shop and will work on older bikes if you decide to take it in...

if youre anywhere near S.E. michigan i would recommend MiCarl at thundervalley powersports...

 

There are plenty of advice on this as most owners have to tackle this problem.
In my experience, it is a fairly straightforward task with only the holding of the internal shaft a small problem.

http://xjbikes.com/Forums/viewtopic/t=15793.html

read up about it, get the right components, and away you go...should be a morning's job.

Enjoy the satisfaction of " doing it right yourself "

 

:lol: Spoken like a true 650 owner. You and I have the anti-dive forks. I recently browsed the archives looking for people who've done the job on our bikes. Information was sorely lacking in my opinion. I'm not saying it can't be done, but I don't think it'll be as easy as redcorfe makes it sound.

Frankly, I'm dreading the task.

 

I'm not looking forward to that job either, I do like the inverted spark plug socket. Sounds like a real time saver. I'm tempted to avoid the anti-dive part, but every time I try to cut a corner like that it comes back to bite me. I'll try to post the results, maybe it'll help someone out.

 

The "anti-dive part" is really the simplest part of the fork job, because it simply unbolts from the lower tube as one complete unit, and then there are a couple of o-rings between it and the fork tube that you replace, and then spray some carb cleaner all throughout it, and that's pretty much it....there are no real "user-servaicable parts" inside of it! (you can remove the upper "housing" and pry out the plunger and make sure it's nice and clean, too, but don't remove the o-ring that's on it, there is no replacement available for it!!).

Just make sure you note in which order the various pieces of the "oil lock assembly" come out, so you can put them back in, in the same order......

 

When I did my fork seals, I took off the anti-dive unit, and it never got put back on! I just found a couple bolts to plug the holes with a little GOOP on them and their now sealed. I never liked the anti-dive units on there anyways. It don't seem to ride much different now anyways. There's maybe a little more dive in the front end, but hardly noticeable.
The seals are easy to replace if you take your time and go by the rules. Keep things clean and you'll do just fine.

 

You'd help me out!! (No pressure, of course ) I'm having the issue of my 900 shocks not holding air. A rebuild is in order. I'm not sure what to do about the anti-dive. It doesn't work(I don't think) anyway. Hit the brakes and the thing still dives like a damn submarine on high alert...oh well. Keep us posted!

 

Thanks for all of the suggestions and Info. After looking at a repair/service manual I see that they want the forks completely disassembled. I think that I may just contact the local yamaha dealer and get an idea of what they will charge me. I have the worst luck and don't want to find out the hard way that I didn't do something right.

 

Forks looks very comlicated in an exploded diagram.

They magically become much simpler when you take them apart.......

 

Glad to hear that Len. They seem to be very linear. I guess as long as you line up the parts in the right order and in the right orientation, they should go back together.

I'll be dropping another couple of parts orders soon.

 

LOL That is true of many things. The corollary is (many things) magically become more complicated when you try and reassemble them.


However forks are not in that category. :lol:

 

I would weigh in that they are not hard...take some time to diagram as they come apart. Two bits of advice.

To hold the oil lock: I took a 5/8 x 24" all thread, used a grinder on one end to make it 4 sided, squared and fairly sharp. Tighten two nuts on the other end, wrap the threads with masking tape...presto, a 2 foot easy out to hold the lock assy. Put the easy out into the fork tube, invert, put the two nuts in a vise, then slide the lower tube on and torque the bolt.

2nd
To seat the oil seals etc. I took a 1" schedule 80 PVC coupling, used a hole saw to drill out the ID slightly to fit over the 36 mm fork tube. Then bought some ABS bushings up to 2", hooked to a 2"x24" PVC pipe, put a cap on the top and then I could use a hammer to tap on the length of pipe & seat seals etc. Hint: glue the 1" couple into a 2" ABS bushing. the ABS glue will harden overnight and provides stability when tapping on it. Don't glue the pipe/cap to bushing...you want to take these apart when working on other bikes, stuff. I used the 2" to tap in an axle seal on the truck. (Use a chop saw to cut all pieces square.)

Lastly,
Don't buy after market seals from Dennis Kirk etc. Get them from Chacal. There are differrences in the seal and washer thickness.

 

Leoks, the task may appear daunting to you now but I can attest that the money you spend having someone else do it will be much more than the cost of purchasing a few tools for yourself and striking out to do it yourself.
I was intimidated by the first set I tackled however, I found them to be very straight forward once I had a clear place to disassemble the forks and took my time. Preparation is important as is cleanliness and order. Read through the process a few times and ask any questions you might have here. There are a few threads on this issue available so look them up.
Steer clear of aftermarket seals, they are short lived compared to the the factory seals.

 

After reading over these posts and looking at the manual again I have decided to make this repair myself. It really does feel good to make a repair like this on your own and do it right.

It actually does appear to be a pretty straight forward repair. My initial question would be about constructing "special" tools to take things apart or to reassemble the forks. I remember when I was younger my step-dad did things like that all of the time.

I don't have any scrap lying around and my tool supply is limited. Where can I buy these "special" tools, such as the handheld press and this longer tool to hold the oil lock? That really seems to be my only issue, at this point. That and any suggestions where to order the proper seal kit I will need. I assume I can get it from Chacal?

I am in Salem, OR.

Thanks again everyone.

 

TAKE PICTURES.

 

Chacal should be able to provide all you need. You shouldn't need a press we used a PVC pipe on Arties X like described above.

 

I used a large metric socket I had laying around if you dont have anything else around to use.

 

I'm doing mine today. Got one fork completely disassembled at this point. Any suggestions on cleaning while I'm in there? Any other points, not covered in the Haynes manual, I should hit?

Thanks,
Paul

 

Hi Paul - we found corrosion where the seals sit and at the top of the forks where on the x the top plug screws in. I didn't see anything else that would really require attention.

 

I just rebuilt my forks a few days ago (Thanks Chacal for the parts!) and the biggest piece of advice I can give you is print out the assembly diagram for them and have it sitting in front of you on your work bench. The entire job is straight forward, however, time consuming. It took me about 2 hours to do one fork, and then another 1.5 hours to do the other.

Take your time and make sure you assemble everything in the right order. When I rebuilt the first one, I noticed that I forgot to put in the taper spindle (xj 700n) and had to disassemble the entire thing to put it back in there. I am not sure of the similarities between the xj700 and the 900, but if you need any help along the way let me know.

 

Well, after getting my first one completely apart, I was a bit lost. There were several parts listed in the Haynes manual I didn't remember seeing. So, I decided to take the second one apart and put the parts for the first one in order piece-by-piece as I went along.

What I found was: Haynes' breakdown of XJ750RJ forks does NOT match my forks. Specifically, where Haynes shows an O-ring below the oil seal, mine have a cup shaped washer, and the oil lock assembly is pretty much entirely different than what Haynes shows.

The oil lock is where I have a problem, though. In mine there's a conical piece that fits onto the bottom of the damper rod where it pokes through the stanchion. Below that conical piece are a shim and what looks to be a spring shim (either a spring shim or a shim that got bent at some point - like when trying to pull out the stanchion from the lower assembly). Anyway, one of the (spring?) shims is broken. Since that part isn't on my Haynes IPB, I'm not sure what to do next.

So... Help!

Anyone else seen this form of a SECA 750 fork? If so, were the lower pieces spring shims or just shims?



Thanks,
Paul

 

On the XJ900RK it is unnecessary to remove the anti-dive unit from the fork lower to replace the seal. Just leave it on.

Here is the place where you can screw up, and the book warns of this: You use the inner fork tube as a slide hammer to knock the seal and outer bushing loose (make sure the spring clip is removed). When you slide the inner tube back down to hit it again you MUST be gentle and try to avoid bottoming it out. At the bottom is the oil lock mechanism and it is VERY fragile. You don't want to bang on it. Do it the opposite of sex - in slow, out fast and hard.

 

Well, I just double-checked my Haynes book, and it does not warn you about the possibility of damaging the oil lock.

Regardless of whether it was me, or it was already damaged, the damage is done. My question still stands, especially since Chacal does not list oil lock assemblies or parts in his catalog: "are these pieces shims or spring shims?"

Also, I'm guessing that the order in which the parts came out of mine is not the order in which they actually sat in there, and they probably should match the IPB. That would make the cup washer versus O-ring discrepancy the only difference.

Thanks,
Paul

 

SQL.....they are spring shims, and go check out the info here:

http://www.xjbikes.com/Forums/viewtopic ... tml#137702


UPDATED: you are right SQL, one is flat and one is a spring washer....but I'm not sure which one goes in which order within the tube!

 

Hmmm... OK.

In mine, the lower piston ring and the oil lock valve itself seem to be fairly solidly installed (or stuck) in the bottom of the fork leg.

As to the "wave" washer... two of mine are perfectly flat. One's a bit wavy, and the other one's broken. Do you stock them? Or can you suggest replacements?

Thanks,
Paul

 

Hey Paul, unfortunately I'm plum out of those little wave washers......and don't know where to get them.

 

We'll, I guess I'll have to see what I can find at ACE. Worst case, I can make one out of some somewhat thicker spring steel I have here, and grind it thinner.

I'll let you all know how it goes.

Cheers,
Paul

 

Hey SQLGuy. I'm at the exact same point as you in reworking my forks. Have one apart and just ordered my parts from Chacal.

Isn't it nice when you spend an hour scratching your head trying to match the parts that just fell out of your fork to the parts sequence in the manual and then find out the manual is wrong!!! I guess it's one way to get to know your bike inside and out.

 

Yeah, I suppose... though I would have thought my bike already had enough hand-made parts!

By the way, how do those shim washers look in your forks? Are they all wavy, or does each fork have one wavy and one flat?

Two of mine are definitely flat. It seems to me that, if both were wavy, I could replace them with one thicker wave washer; if both were flat, then they probably would have used one shim to start with; and if only one is wavy, then their use of two makes much more sense (as one would act as a spring for the valving of the oil lock, while the other would do part of ensuring a minimum gap between the cone-shaped washer and the bottom of the stanchion).

 

Hey guys...same with me, one spring (wave) washer was broke. You cannot get replacements. You will have to find an old fork and scavenge the sping washer.

Here is what I did:
Bought 2 nylon washers. Used a flat grinder to make them fit perfectly above the oil lock valve (the cone shaped piece). In this fashion, the oil lock assembly never by-passes fork oil. No adverse effect as I have test ridden mine. Possibly a little stiffer on the compression.

Second option:
I bought spring washers from Seastrom Mfg 800-634-2356 part # 5804-326-2 for $12.66. These washers are just about the correct diameters. Problem, almost 2x the thickness which means they need more pressure to compress. This will change the closing of the oil lock valve. Don't know how they will work. Next time I open the forks I will try them.

UNLESS someone sends me one good original spring washer!! Then I'll have a set and will put it back to stock.

 

I carefully removed the washers, noting the order that they lay inside the aluminum casting that rests at the bottom of the bottom tube. There are two washers, one wavy and sits in the bottom, or first into the aluminum casting. Next is the flat washer. See pic below.

Also, Apparently, the fork tool that everyone makes or buys won't work in our 750 Seca forks because the top of the damper tube is round and not hex to accept the spark plug socket end or tool. I'm lucky I read the note on the XJCD's suggesting to break free to retaining bolt before removing the forks. Mine broke free with no problem. I removed them to drain the oil prior to fork removal. I'm hoping that I will be able to tighten the bolt with no positive way to hole the damper tube from spinning. I'll probably make a wooden dowel to press onto the top of the damper while tightening the retaining bolt.

 

Excellent information. That's exactly what I needed to know. Thanks Carl!

I stopped by ACE, but came up empty-handed... nothing even close.

So, plan B will be first to make a small shellac face plate for my mini-lathe, then to shellac some .25mm spring steel sheet to it. I'll use the lathe to cut the ID and OD, and maybe to face off the "extra" .1mm of thickness. Probably finish up with a fine diamond sharpening stone. Should know how well this plan works out later today.

Len, if you want to get a set made, Misumi was mentioned on one of the machining forums as a good supplier for small-quanity custom shims and wave washers along the lines of what's needed here.

Cheers,
Paul

 

Carl, way to go, thanks!

Paul, I'll look into it. I know that those wave washers are almost always deformed or broken, and so it's a part that needs to be made.

 

Well hopefully I don't have those same problems when I work on my forks. I ordered my parts from Chacal and hopefully I will be able to start in the next few weeks. The weather is getting better here and I am ready to ride.

Thanks everyone for your help and I'm sure I will need some assistance in the future.

 

Success! I think/hope anyway...

It took three tries, and I had to make a couple of different new tools for the lathe, but I managed to make a fair copy of the broken wave washer.

The forks are now back together and I'll install them either tonight or tomorrow night. I used a piece of 1 1/2" PVC for the bush and seal driver (had to taper one end a bit with the bench grinder to make a good fit). It worked well, and seating the bushes and seals was actually pretty easy.

Cheers,
Paul

 

leoks,

I might suggest also looking on YouTube. I didn't find my exact forks there but there were lots of videos of fork replacements for different motorcycles. By watching enough of them, I was able to find enough variations to cover most of the features of my forks.

It gave me a good sense of what to do. Didn't hurt that I also had some help from bill.

 

SQLGuy, Wow, you don't mess around. I've always wanted one of those mini lathes. Congratulations on making the spring washer. It looks great.

 

When I rebuilt the forks on the XJ750E-II I found that the previous owner had lost some of these Lock Valve "shim washers". After some investigation I found that the Yamaha Venture had the same arrangement and I ordered the genuine Yamaha parts using the Venture part numbers.

 

Kiwi, I think the 750E-II uses the same forks as the XJ900 models? And those shims are not the same as the XJ750 Seca model shims........although they are VERY similar.

The 750 Seca shims have the following specs:

ID: 15.55mm
OD: 20.85mm
Thickness: 0.14mm
amount of bow, resting: 1.60mm


The 900RK Seca shims have the following specs:

ID: 16.15mm
OD: 20.85mm
Thickness: 0.21mm
amount of bow, resting: 1.25mm



So the 900 shims have the same OD, but a bigger ID (which shouldn't matter, that means for sure they will fit over the 750 Seca damper rod shaft), but they are 50% thicker than the 750 Seca shim, and have less "bow" or height to them in their un-loaded state.

NOW, these are certainly very thin shims, and can't exert a whole bunch of pressure (control) to begin with, BUT.......perhaps not much pressure, or, very precise control IS needed in these contraptions. And although my "spring rate calculation" formulas and knowledge is really, REALLY rusty, I do recall that the thickness of the wire (or in this case, the shim stock) is a huge determinent of the final spring rate, and I just don't know what (if any) effect using a different tension spring is going to have on the functioning of the forks (good, bad, or down-right scary-ugly),


By chance, you wouldn't happen to remember what YEAR and MODEL of Venture used those style shims, do you?

 

I just got mine taken apart this weekend. The flat washer came out with the tapered cone, but no wavy washer, hope they are not damaged or lost, I will check tonite. The hardest part of the disassembly for me was getting the dust seal out without damaging the bottom tube, of course cleaning up fork oil everywhere was no picnic either. The hex head special tool was useless on mine too.

 

UPDATE!!! So I have everything apart & all has gone pretty well. I will be putting it all back together in the next few days. My questions are about "pressing" the oil seals & stuff in. I read about getting the 1" PVC, can someone explain this a bit better or give me any other ideas? The fork that had the blown seal was MUCH harder to get apart than the other fork.

All the tools and parts I ordered from Chacal are working great at this point.

 

PICTURES.

 

Actually, what I used was 1.5" PVC. I used my bench grinder to grind a bit of a taper on one end. Original OD was 48.3mm, I ground the taper down to 46.5mm or so. This allowed it to just fit into the fork leg opening. Overall length about 21".

To use it, I clamped the fork leg in my vise's round object jaws, wrapped in one of those foamy lattice place mats. I put the stanchion in place in the leg, and use the PVC, with a small block of wood on top of it and driven by a hammer, to seat the boss... similar use to seat the seal (with grease inside and out), and dust cover (also greased).

Cheers,
Paul

 

Thanks for the pic and info SQLGuy. I bought some PVC pipe last night, but I need to get one more piece that is small enough to seat the bushing & oil seal. Last night I cleaned & inspected all of my parts and reassembled the damper rod pieces.

Tonight I hope to get the seals seated, the oil measured and everything buttoned up so I can put it all back on the bike. Wish me luck, so far there have been no major problems on my part. Which is a small feat in itself.

 

Ok so I'm done with my seal installation and everything is put back together. I put the recommended amount of air in the forks and took it for a ride. The handling is MUCH improved and I feel more confident riding it now.

However, there is an unusual noise when the front suspension is really compressed. It sounds like a spring being compressed or something. I did install new progressive springs, but I don't know if this could be contributing to the noise or not.

Any ideas or suggestions would be great.

Thanks.