2008-12-26 Replacing Fork Seals and Bushings

Posted 26 December 2008 - 09:07 PM

Blown Gen II fork seal. Got the innards out and inner/outer tube separated.

Question - what have you done to reseat the bushings for reassembly? I called GPS, Ben stated they built special tools to seat the mid and upper busing into the outer tube. What have you used?

Some pix..

The entire assembly. Each bushing is approximately located where it would be when assembled, fully compressed.

Close up of the bushings.

Here you can see where bushings 'bottom out' on the ridges. The 'middle' bushing sits about 4 - 5 inches deep from the seal, the 'upper' bushing sits just below the seal. Ben said the upper bushing can be driven in place by using the flat washer and normal seal driver + heat.

Another whole picture shot..

And finally, a little motobike juxtaposition at 38 degrees F.

Soo, for you do-it-yourselfer's, what have you used to seat these bushings?

PVC pipe?

Yamaha high dollar fixture part?

?????

..to be continued

Posted 27 December 2008 - 09:19 AM

For clarification, this tool will seat Gen II bushings? The 'middle bushing' sits approximately 4" deep in the outer tube, and is the difficult one I've been told to get seated correctly.

Sorry dcarver, I'm not answering your questions; but have a related question on the procedure. If nothing else this will at least bump your thread

Did you use the car jack method to pop the fork seal?

No, I don't even know what that method is... I simply clamped the outer fork tube into a soft-jawed vice, applied heat to the outer fork tube using a propane torch (heat from outer fork tube lip down about 6 inches) until it was just too hot to touch by hand. Gently but firmly pull the inner tube out, using it as a slide hammer. Use multiple hits. Keep applying heat. I destroyed my bushings by not applying enough heat and popping the tubes with too much force, causing the middle bushing to destroy the lower bushing.

My first time, I'm still much better off $$$ wise than having a shop do it, and know I know better!

..to be continued

Posted 13 January 2009 - 07:00 PM

Guess I'll post back to my own thread .

I've been to every hardware store in 4 counties looking for just the right size pipe. PVC, EMT, fence poles, plastic sewer pipe, electrical pieces n parts, blah blah blah. Looked like a goofball with my digital dial calipers measuring everything in site.

I tried 2" copper pipe, sawed in half. It's not deep enough to work effectively nor does it have an area to 'hit' in order to drive the bushing home.

Then yet another bright idea entered my cranium scareabellium.. What about a muffler shop? They can 'expand' muffer pipe using hydraulics... yeah, that's the ticket.

Only problems?

1. Muffler shop could only 'poof' pipe in ~2 inch sections. To drive the bushing home, I need a section about 13" long.

2. The fork tube at the tip flares out, which I didn't notice until I got home and attempted to slide the sleeves over the inner fork tube top.

In the meantime,

1. I'm still waiting on parts (bushings, seals, washer) from good ol' Gary McCoy

2. I have some hope in having a custom made bushing driver created by some talented folks who swore me to secrecy pending how well it works.

3. I found a local independent shop who said they would drive both bushings home for 1/2 shop rate, or 45 bucks. Since I want to get Crzy8 back on the road (it's been 2 weeks now), I may just spend the $$ on the shop then continue this quest for a good part. I sure wish I had my own lathe, I know how to operate them and this would be so over. Hmm, now I think of it, I wonder if they would sell me whatever driver they use?

Sooo, fellow Feejer pilots, any other ideas? Or do ya'll just pay the shop prices?

..to be continued

Posted 29 January 2009 - 06:43 PM

Ok, I measured the sleeve GPS made for me:

ID = 48.05 mm

OD - 51.05 mm

Wall thickness = 1.55 mm

Haulin', I was thinking, that for simplicity, if the sleeve was long enough to extend past the inner tube top, when the inner is fully inserted into the outer, the sleeve could be hit with rubber or brass mallet to directly drive the middle bushing into place. If the sleeve had a 'cap' then the cap would take the abuse of the hit and not distort the sleeve.

I'm not sure what would be easier to machine, a longer sleeve with PVC cap (or whatever)

or

your idea of an 8" sleeve with heavy metal ring, kind of like a non-sliding slide hammer.

I will say that it doesn't take much force to seat the bushing, especially if the outer tube is pre-heated to expand.

Whatcha think HA? You're more of mekanic than I am..

I'll cut and paste this as PM to Just Roy to see if he's still interested.

..to be continued