Strange looking fork cap on a -97 CR250

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Jul 12, 2000
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#1
The fork caps on my -97 CR250 looks like they do on a old cartridge fork. Just one fork cup, for a 32mm wrench, thats it.
Usually there is kind of two on twin-tube forks - right?

In the owners manual (page 87) there is actually one picture with this kind of fork cap, the picture in the middle of the bottom of the page.

The fork looks like an ordinary "gold" anoized Showa fork, and inside it's look like an twin-tube.

What is this, can I use my manual on this fork ?
 
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#2
The '97 CR show forks used caps that threaded onto the cartridge tube and then the outside threaded into the fork leg.
disassembly:
1. use a 32mm socket to remove the cap from the outer fork tube.
2. loosen the small grub screw (set screw) enough to clear the threads on the cartridge tube. If its your first one just remove it altogether.
3. use a very big adjustable wrench to hold the cartridge tube by the flats. The wider the jaws the better. Be careful if you decide to clamp the cartridge tube flats in a vice. It's possible to crush the tube!
4. Loosen the fork cap from the cartridge tube with a 32mm socket. It's locktite'd so it takes some doing and the sounds it makes comming loose will make you cringe.
5. before removing the damping rod from the cartridge use a wire wheel to clean (kind of burnish) the thread on the end. This is so the seal inside the cartridge tube is not damaged.
6. Remove the damping rod.
7. Clean the parts.

Assembly
1. Insert the damping rod.
2. fill the cartridge with oil to the step in the tube.
3. pump the rod to bleed the air from the system
4. fill the cartride with oil to ~5mm above the step
5. insert the cap assembly (this takes a bit of force but can be done by hand) and thread the cap onto the cartridge and tighten.
6. insert and tighten the grub screw
7. pump the cartridge rod to full stroke. You'll hear the oil blow off into the top of the cartridge.
8. empty the excess oil from the top of the cartridge.
9. reinstall the cartridge into the fork leg.
 
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#3
Thank You!

Thanks mxneagle.
Your explanation was much easier to understand than in the manual...
And I'm also a little more comfortable knowing that the former owner didn't screw me up - For a while I thougt He had sell the bike to Me with some old fork laying around...

Dvraptor
 

Jeremy Wilkey

Owner, MX-Tech
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#4
MXEagle,
I think you would be wise to mention how to protect the seal during reasembly.. Your method will quite likely damage the seal..

Regards,
Jer
 
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#6
Well, I've rebuilt my twin chambers many times without using any protection other than dipping the threads into fork oil before installing. I haven't had any seal problems, but now that you bring it up, at a minimum I will use the tip of plastic sandwich bag the next time I do it. The only better way that I can think of is to make a bullet shaped cap for the end of the damping rod with very thin walls that fit over the threads. I'm not sure if thats really required though.

Care to share your method with us Jeremy?