Thread for Rebuilding Honda XR500/XL500 Dual Shocks

A very knowledgable and helpful forum member (Muzz67) advised it is possible to do this with good results, and encouraged I give it a shot.  I'm making this thread to document the process, and as reference for other who might want to try it.



First, disassembly:

I started out by putting one of the shocks upside-down in a vise.  I'd strongly advise using a vise for this project, but you may be able to do without.


I used a ratchet strap to to compress the spring and remove the retaining disc which sits between the bottom eye and the spring.


I removed the spring and disc:

Edited by wearetheroadcrew

Now you can see the top of the internal parts of the shock.  To remove them, you need to get to a snap ring that sits just out of reach.  This was the hardest part for me.


I started out by flipping the shock upside down in the vise so I could hold the eye and remove it from the shaft. Then I used a lockring pliers (I actually made these ones out of an old set of channel-locks) to remove the cup peice that is threaded against the eye.  A regular lockring spanner will do the trick.


Now, turn the shock back over.  To get to that snap ring, you must compress the internal portion of the shock about a centimeter.  I did this by pushing the shaft all of the way into the shock, and setting a 1/2" drive socket on top of the shock.  THen I used a ratchet strap to compress the internals and expose the snap ring.


You can see there are a couple peices of wood in the vise to protect the shock.  It takes coniderable force to compress the internals.  I though something was going to break it, but then they moved.  If you have trouble, tap the top of the socket with a hammer to loosed things up.  When it moves, you should be able to see the snap ring.  The snap ring is also tough to fish out.  I used a precision screwdriver and the tip of a zip tie to manuver it out.


Watch out - when everything finally comes apart, there will be a little spray of oil - it's worth wrapping a shop rag aroung the end of the shock before it comes apart.

Edited by wearetheroadcrew

Once the shock is apart, you will have two peices - The body and the internals


The internal part contains the o-ring and the seal, which we are replacing.


The body just has a bunch of old oil in it.  There was about 200ml left in mine.  You put it upside down in the vise, so the oil is still contained in the body.

Slide the movable part of the shock internals off of the shaft.  Peel off the O-ring. Flip it over and remove the snap ring, which will allow you to get at the seal inside.


These two rubber parts create the seal against the shaft and inside of the shock body.  They are the consumable parts we will be replacing.  As far as I know, Honda doesn't supply replacement seals, so I'm going to source the seal from a metric hydraulic seal provider.  By my measurements, the dimensions are


ID = 12mm

OD = 24mm

Width = 5mm


The O-ring is a standard metric O-ring, as far as I can tell.


I haven't ordered the seals yet, but I'll post a link and description when I find it.

Edited by wearetheroadcrew

Now comes the interesting part.  The goal is to attach Schrader valves (the kind found on innertubes) to the shock bodies, so they can be filled with oil and nitrogen.  To do this, we will drill small (3mm) holes in the shock bodies and braze the valve stems over them.


I'm terrible at brazing, so I'll be dropping the parts off with a friend for help.


These are prepped to go.

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