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Fork seals and the tech page

xjdaver

xjdaver

Bicycle
Just a couple of questions:

What is the best method for supporting the front end?

Any idea what size PVC is required for the homemade seal installation tool?

No mention of either in the tech page. I do have a Clymers at home. It probably tells how to support the front end but maybe someone here knows a better way.
 
I'm afraid I cannot help on the seal driver sizing, but as for supporting the front, there are lots of ways.  Here are some I've tried and all worked.

1.  Put bike on centerstand and tie handlebars or frame backbone to ceiling joist to support.
2. Put bike on centerstand and use floor jack and/or blocks to hold the front up.
3. Use bike jack to lift entire bike off ground.  This is easiest since you can move the bike while having forks off and can lift it higher for dismantling.  It gives more capabilities.
4. Put bike on centerstand and tie rear of bike to floor anchors via the pillion handles.
5.  Put bike on centerstand and placed a bag of cement (80 lbs.) on the rear rack (not stock rack).
 
The pipe size I used is 1 1/2" schedule 40, either PVC or ABS.  The hardware store where I got mine doesn't have short lengths of PVC, but does of ABS, so I used that, and it worked great.  Split the pipe down its length on one side, since its I.D. is slightly smaller than the O.D. of the fork tube.  With the split, you can slip the pipe over the fork tube and drive the end of the pipe to seat the bushings and seal.

HTH,
 
Slybones said:
Take lots of pictures and send them to me. I'll update the tech page.
Click to expand...

Hey, which Tech Page?  I see the French-translated version of fork seal replacement here:
http://www.gtrmania.com/upload/Download/Kawasaki_GTR1000_Front_Fork_Oil_Seal_Replacement.pdf

This is a comprehensive article for the pre-95 C10 but I want to know if we have one here on the forum, in original English, for the post-94 C10.  I've searched our Tech Pages and only find:
http://www.cog-online.org/clubportal/clubstatic.cfm?clubID=1328&pubmenuoptID=30801

The above Tech Page isn't a step-by-step tutorial, which I was hoping to find. Is this the only Fork Seal replacement page we have on our site?

Thanks.  I've got two 97 Connies, ride full-time, and put about 40K per year on them. This is a great help. 
 
GFinCA said:
The pipe size I used is 1 1/2" schedule 40, either PVC or ABS.  The hardware store where I got mine doesn't have short lengths of PVC, but does of ABS, so I used that, and it worked great.  Split the pipe down its length on one side, since its I.D. is slightly smaller than the O.D. of the fork tube.  With the split, you can slip the pipe over the fork tube and drive the end of the pipe to seat the bushings and seal.

HTH,
Click to expand...

To points to consider, one is that you should make sure there is nothing inside the pipe to scratch the fork if the pipe slides a bit. I used the old fork bushings as I didn't have the right size pipe handy. I put some masking tape inside the bushing to pad it a bit.
Second, it might not hurt it, but I don't think the seal lip is the best place to push on the seal. I solved that by using four of the old bushings, with one being over and sticking out from the one, so that it pushed on the metal part of the seal.
 
Good point on not getting any grit between the driver an fork tube.  The plastic pipe itself is fairly slick, and shouldn't do any damage by itself.  The wall thickness on the sch 40 pipe is thin enough to fit in the counterbore for the seal so you can drive the bushing in, yet is still large enough to engage the metal reinforcing in the seal, so the lip of the seal doesn't have much, if any force put on it.  Your method if using the old seals works well, too.
 
If I had thought of it at the time, I would have used a triple clamp in addition to the hose clamp. The hose camp would not tighten enough to prevent sliding, so clamping the triple would have backed up the bushing and the hose clamp would only need to keep the bushings on the tube.

Also, I had rust on the retaining rings, probably a good idea to put some grease in there to prevent rust.
 
WillyP said:
If I had thought of it at the time, I would have used a triple clamp in addition to the hose clamp. The hose camp would not tighten enough to prevent sliding, so clamping the triple would have backed up the bushing and the hose clamp would only need to keep the bushings on the tube.

Also, I had rust on the retaining rings, probably a good idea to put some grease in there to prevent rust.
Click to expand...

I don't have a vice.  Is this necessary?
 
You can do it without a vice, but you may need to clamp the fork to your bench to remove and reinstall the damper rod.
 
I did it without a vice. You don't need a vice. I rebuilt the forks outdoors on a folding table. But, you need something to clamp onto the fork tubes. Then slide the fork tubes to drive first the upper bushing then the seal into the lower fork. It does not take a lot of force, but using a hose clamp I did not get a great grip and the old bushing, which I was using to drive the new bushing and seal into the lower fork, was not quite strong enough, and I had to reposition and retighten it quite a few times. I had the upper triple off the bike any way. It would have given me much greater clamping power, if I had though to use it.

I did use the triples to clamp the upper fork tube when r/r'ing the damper tube, and that worked the balls, I also put an open end wrench on the lug for the brake caliper.

I was also concerned about the socket in the top of the damper being damaged, it does not look all that strong to me. So I put the final torque on only the screw, no wrench in the damper rod.

Pictures: Fork Rebuild  Gallery
 
I've begun to tear down a spare set of forks I have.  I have a spare upper triple clamp from a complete set of locks I have laying around and used that to secure the forks while removing the top plugs. 

I've read through the Sig & Fefe fork seal PDF and the Service Manual and my next step is to remove the Allen bolt from the bottom.  I have a 3/8" drive hex bit which fits into the bottom but I'm not clear what size nut-and-socket assembly to use for the Special Tool that fits inside the tube.

I read another post here that suggested jamming the whittled-down the end of a wooden broom handle to prevent the inside from turning while loosening the allen bolt so I'll try that first.  Once I have one of them apart, I can get fabricate a nut-and-socket assembly for additional disassembly and reassembly.

Thanks for the fork rebuild photo gallery.  It's very helpful to someone who hasn't disassembled this type of assembly before. 
 
Per WillyP's advice, I'll be using either 15/16" nut-and-socket assembly to keep the damper from turning when removing the bottom allen bolt from my forks.  A 24MM is nearly the same size too.
 
24mm is probably the right size, but 15/16 is the socket I had that fit the nut I borrowed off my jack.

edit: McMaster-Carr has a coupling nut that I think would be the balls for this. A coupling nut is longer than a regular nut, so you would not have to use something to keep it from sliding into the socket too far. Coupling Nut With Sight Hole #93525A315
 
That McMaster-Carr item looks like the bomb.

My damper-rod-removal solution was to go to the nearby Ace Hardware with one of the forks I had drained of oil.  I was determined to test out 24MM and 15/16" sockets and nuts.

I brought with me a bunch of 1/2" and 3/8" socket extensions, not knowing which size sockets Ace would stock.

I tested a 24MM socket and also a 15/16" socket.
I checked different nut sizes in each socket.
The 24MM nuts were a slightly tighter fit in the 15/16" socket (and it was a buck cheaper than the 24MM socket).

I made a stack of two 24MM nuts and one washer, in-between the nuts. This left about half of one nut projecting above the rim of the 15/16" socket.

I then checked this assembly in the fork and found that 24MM nuts felt a little tighter in the head of the damping rod. 


My final tool is the stack of two 24MM nuts with a washer spacer in a 15/16" socket.

I took it home, taped the nuts and washer into the socket and had my forks apart within ten minutes (they had already been gravity-drained of oil).

Thanks again for the tips and suggestions.
 
I disassembled both forks and completely cleaned out the old, stinky fork oil with a couple quarts of mineral spirits.  It seemd to me like the the bottom end of the inner fork tube is best cleaned by pouring mineral spirits into the smaller side holes.  I very happily ragged everything dry and they're now sitting on my kitchen table on a nice bath towel :)

I've studied and read numerous posts about installing new fork seals.  I bought a length of 1-1/2" ABS to drive the new fork seals into the lower/outer tube housing.

Here's what I think I need to do. 
Since the ID of 1-1/2 Schedule 40 plastic pipe is about 1/2MM smaller than the OD of the inner fork leg, it dawned on me what the articles and posts meant. 

Originally, I thought the plastic pipe would be slid up-and-down (like a slide-hammer) on the upper/inner fork leg to drive the fork seal into the seat on the lower/outer fork leg.  I could not wrap my head around this since the ID of the plastic pipe is smaller than the OD of the upper/inner fork leg.  How's that supposed to slide, I wondered??  :-[

But, after disasembling my forks, cleaning it all up and studying the way they fit together and interact with each other, I see what needs to happen.

First, I will reinstall the damper tubes.

Then, I need to take a short (like 2") kength of the 1-1/2" plastic pipe, cut it lengthwise so it will expand enough to fit over the upper/inner fork leg.  I'll slide the bushing and washer onto the upper/inner fork leg, then, expand/lengthen the fork assembly, and slide the 2" piece of plastic pipe over the upper/inner fork leg until it rests a few inches above the bushing washer (again, with the forks extended).  Then, I'll clamp the 2" piece of plastic pipe onto the upper/inner fork tube with a couple of hose clamps so it can't move.  I might wrap some masking tape over the upper/inner fork leg so the plastic pipe has something to grip onto. 

Finally, I'll place the fork upright, with the bottom end of the lower/outer leg resting on a block of wood and, using the upper/inner fork leg, drive the fork seal down into its seat on the lower/outer leg.

I'll repeat the process with the new fork seal.  The new fork seal is an all-rubber seal and will probably seat with minimal effort.  I'm more concerned about seating the bushing and will definitely lube it with a film of moly grease before driving it in place.

My biggest stumbling point in this part of the Fork Seal R&R process was in thinking that the piece of plastic pipe was supposed to be used like a slide-hammer.  I see now that it's supposed to be clamped stationary--onto the upper/inner fork leg--and that the sliding action of both fork halves, moving towards each other, is used to seat the oil seal and/or upper bushing in place on the lower/outer fork leg section.


I hope this helps someone in the future.
 
If your fork tubes are scratched you might want to polish them up a bit. Here's what I did: After completely dissembling and cleaning the forks, I put the fork caps back in the tubes and chucked the preload adjuster in a cordless drill. I set the other end down on some rags and spun the fork tubes at medium speed. If you have a lathe, you can use that. Use some fine grit and wrap it in your hand around one end, move very slow to the other end. If there are deep scratches, you won't remove them completely, as you might sand through the chrome. Just enough to remove sharp edges. While you are at it, remove the sharp edge from the end of the tube, that could cut the seal as you slide it on.

Also, make sure your pvc is cut off square, you don't want to **** the bushing. It goes in pretty easy, use fork oil to lube it. The seal is a little harder. Make sure the bore it goes in is clean, and be careful not to damage the lip when driving the seal in. Ideally you would have a tool that contacts the outside perimeter of the seal. I used the old bushings and set one over the other, so the outside one contacted the seal, the inner one left a gap for the lip. Others have said it is not necessary, that they drove the seal in the way you described and the seal was not damaged.

 
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