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suspension fork repair - inflation valve



 
 
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  #1  
Old February 25th 04, 10:19 PM
Brian
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Posts: n/a
Default suspension fork repair - inflation valve

i'm attempting to salvage a vintage specialized fs carbon/titanium
front fork. the problem is that the right leg no longer holds air,
i.e., after inflation you remove the needle and all the air comes
right back out.

i've taken the leg apart and it appears that the small (1.5cm length x
0.5cm diameter) rubber valve that the needle passes through has been
torn. this piece sits right below the removable screw on the top of
the leg. i'm wondering if it is possible to get a replacement piece,
scrounge a replacement out of an old basketball, repair the piece with
some sort of adhesive, or if it is best to just update the fork.

any advice is greatly appreciated,
b.

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  #2  
Old February 27th 04, 05:09 PM
moparfreak
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Default suspension fork repair - inflation valve

(Brian) wrote in
om:

i'm attempting to salvage a vintage specialized fs carbon/titanium
front fork. the problem is that the right leg no longer holds air,
i.e., after inflation you remove the needle and all the air comes
right back out.

i've taken the leg apart and it appears that the small (1.5cm length x
0.5cm diameter) rubber valve that the needle passes through has been
torn. this piece sits right below the removable screw on the top of
the leg. i'm wondering if it is possible to get a replacement piece,
scrounge a replacement out of an old basketball, repair the piece with
some sort of adhesive, or if it is best to just update the fork.

any advice is greatly appreciated,
b.

--
rec.bicycles.off-road is moderated by volunteers. To find help solving
posting problems, or contact the moderators, please see

http://rbor.org/
Please read the charter before posting:

http://rbor.org/rbor_charter.txt



If you can find a dealer for "Total Air" they offer air cartridges to
retrofit many different styles of forks (rock shox, marzocchi, etc) to a
fully modern dual air cartridge system with schrader valves. This might
not seem like the most cost effective way, but the extra money you put
into it now will save any headaches down the road (hooray for 2 year
warranties!) and it will have that super-cool looking vintage unit on the
front of your bike performing just as well as a brand new Sid for a
fraction of the cost.

--
rec.bicycles.off-road is moderated by volunteers. To find help solving
posting problems, or contact the moderators, please see http://rbor.org/
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  #3  
Old March 26th 04, 03:43 AM
Patrick Smith
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Posts: n/a
Default suspension fork repair - inflation valve

That's a really cool fork. I have one, new, waiting for the right
project bike to install.
The internals are idenitical in function to the RS MAG 21, I'm
pretty sure. I heard that the Specialized FS forks that used air oil
were essentially MAG 21s that were assembled by some company other
than rock shox. I cannot confirm this completely as I've yet to take
a SPEC FS apart. I also own a Magnesium SPEC FS that is identical to
the RS Mag 21 in apparently every way, from outward appearances.
The air seal you talk about is called the air cap on MAG 21s (was
also used on early SIDs, I hear). When removed and inspected, it is
nothing more that an aluminum sleeve filled with some kind of flexible
cured plug that has a tiny star washer jammed up against it. The star
washer apparently keeps the cured, flexible plug from being pushed out
by the use of the inflation needle.
The inflation needle is inserted into the alum sleeve and through a
hole in the flexible plug.
Here's the trick. I have not tried this, but mean to. Drill out
the star washer, and find a way to remove the pug (solvent, heat???)
Be carefull not to gouge the side walls of the alum tube. Squirt some
kind of silcone sealant in to replace the plug, and let it cure. The
silicone sold in small tubes at automotive stores for making engine
gaskets might work best. Go to a well stocked hardware store and find
/ order a new star washer and jam this down the tube to secure the
cured plug. I'd recommend taking an intact air cap into the HW store
to show them what you need. Once the star nut is installed, take a
long, stought nedle and use a thimble to push the needle though the
plug, far enough to poke though the hole in the center of the star
washer.
These air caps used to be available as replacement parts, but were
getting hard to find before the SID came around. The early SIDs
exhausted the easy-find, remaining supply of these air caps. Rock
shox no longer produces replacement air caps.
It is interesting to note that the new, factory supplied replacement
air caps required the repair shop or user to poke the hole them as
described for the home-remedy, above. This confirms to me that the
factory seal probably not a molded part and was not much different
than the proposed home remedy (liquid silicone).
Tip: don't use a sports ball inflation needle to refill these
air-cap equipped forks. The air hole on the side of these sports ball
needles tear up the seals a little bit with every inflation. Buy a
propper needle for RS or buy a shock pump that comes with one. A
propper fork needle will have the hole at the tip of the needle, with
rounded edges to minimize tearing.

Pat Smith



moparfreak wrote in message 9...
(Brian) wrote in
om:

i'm attempting to salvage a vintage specialized fs carbon/titanium
front fork. the problem is that the right leg no longer holds air,
i.e., after inflation you remove the needle and all the air comes
right back out.

i've taken the leg apart and it appears that the small (1.5cm length x
0.5cm diameter) rubber valve that the needle passes through has been
torn. this piece sits right below the removable screw on the top of
the leg. i'm wondering if it is possible to get a replacement piece,
scrounge a replacement out of an old basketball, repair the piece with
some sort of adhesive, or if it is best to just update the fork.

any advice is greatly appreciated,
b.

--
rec.bicycles.off-road is moderated by volunteers. To find help solving
posting problems, or contact the moderators, please see

http://rbor.org/
Please read the charter before posting:

http://rbor.org/rbor_charter.txt



If you can find a dealer for "Total Air" they offer air cartridges to
retrofit many different styles of forks (rock shox, marzocchi, etc) to a
fully modern dual air cartridge system with schrader valves. This might
not seem like the most cost effective way, but the extra money you put
into it now will save any headaches down the road (hooray for 2 year
warranties!) and it will have that super-cool looking vintage unit on the
front of your bike performing just as well as a brand new Sid for a
fraction of the cost.


--
rec.bicycles.off-road is moderated by volunteers. To find help solving
posting problems, or contact the moderators, please see http://rbor.org/
Please read the charter before posting: http://rbor.org/rbor_charter.txt

 




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