XLV shock


XLV Rear Shock
Disassembly, Reassembly and things to watch for.

Disclaimer: a complete idiot wrote this and you must
take sole responsibility for doing anything that is suggested here.
Do take care at all times, there are spring pressures etc to consider.

 

Thanks to a number of people who contributed one way or another.

The XLV shock is not a piece of rubbish but a well built and designed bit of gear!

From what I can gather the only thing that went wrong was a poor standard of material that was used in the rebound cushion inside the damper and the same  for the bottoming cushion housed in the outer chamber. They apparently could break up at anytime, at random, it happened to spare parts just sitting in storage. Not Hondas fault it affected many makers, but the effect would be felt over time as the valving clogged up and the shock was seen to have failed. Looking at the two I have here which are 20000 and 83000 km old there is not a huge amount of wear difference, I would suggest that Honda intended the shock to last a long, long time with only the oil and seal changes as detailed in the manual being needed. Making it "non rebuildable" was an appropriate course. It has huge preload variation with the air assist and good rebound damping adjustment via the push pull adjuster. Neither of my bikes had any trace of this adjuster, I first saw it in the already dismantled shock bought from John. Its that shock that is rebuilt here.
The first instalment about my having cut my original shock off at the base (below) is not what I would do again. I think they should be dismantled from the top with the top of the damper tube being turned off in a lathe or very carefully cut with hacksaw or very fine cut off wheel (Dremmel type). Thats not to say you cant cut the bottom off, it can be welded up too but it is probably easier just to do it the other way.


cutting the bottom end off shows the end of damper assembly, the centre of which (right)
removes easily. Three spacer / shims plus spring. Packed with debris is this case anyway.

   

With the bottom removed and the top cap undone the damper assembly can be removed via bottom BUT it needs to be worked gently to get it out.
SO I BOUGHT ANOTHER SHOCK THAT HAD BEEN DISMANTLED BY ACCESSING THE TOP AND CUTTING THE TOP OF THE DAMPER TUBE OFF (as per Ratman). THAT IS THE UNIT WE ARE WORKING ON NOW, THE OTHER ONE CAN BECOME SPARE PARTS.
So, lets have a look at how my attempt to rebuild this shock went. I have a view to whatever being done being able to be undone to facilitate further rebuilds.
What you need (or need to have access to):
A press, hydraulic but doesnt need to be big, the multi bolt press as used by "Ratman" is fine but as you need to be able to press and repress the shock, a hydraulic is
more practical. A TIG welder and someone who knows how to use it (any good engineering place). I used my good mates at Well Done Engineering at Omeo VIC.
We should really have multiple pages for this but will just make it
one Longgggg page for simplicity. Suggestions and corrections please email
cassilis@activ8.net.au
 		  
First to the honda manual. What it is saying to remove the seal etc is to remove the air valve, turn the thing upside down, put it in press and pump up and down a few times with the air tube in oil. It will draw oil in to fill the air chamber with fluid. Remember that fluid will not compress so when you put the valve back in and press the shock, the seal will be forced to come out, you have removed the stop ring havent you? What does take time though is when you have pressed and released the shock with the tube in oil, because it is drawing oil through a small air hole, it takes time to draw the oil in (so be patient). If you take the tube out of the oil and it draws air (after a second or three) then it hasnt finished yet) BUT when it is done and you turn it over and press again, with the valve in, the seal comes out smoothly not with a bang.
Then its press down the outer tube, remove stop ring and oring.
The outer cover comes off the spring comes off and we have the guts of it.
THE OUTER MAY HANG UP ON THE LIP AND NOT COME OFF CLEAN.
There is still some pressure there, put top mount in vice and turn the outer cover, it will probably "pop" and the vice will take the spring pressure.
Then the top and its locking ring can be removed.
 
We now have the steel cap to be tapped off, its not hard.
When thats off some sharp tugs will bring the damper rod bush out, in this pic the bush
has already been slid off  the damper rod and is sitting separate.

 
 
The enclosed centre in this nut is part of the rebound damper. It should not be removed (even though i tried). The valve plate visible in the small hole
is free turning and is what the damper adjuster turns to vary the damping force. When its undone look from the other side, you will see two holes, one large , one small (low and high damping) and a rectangular slot in the middle, this is what the damper adjuster turns. They line up with the hole visible here.
.		 To remove the nut from the end, I placed the nut in a vice and used the cap and lock ring to undo it. As "Ratman" says it comes of easily without much thread damage BUT you should clean up the thread on the rod with a small file to make sure it goes back on without damage.
 

When the nuts off you can see the three points that were "staked" to retain the nut and the threads (last couple?) that the staking affected are what should be filed
So the rebound damper is all apart, bits of old cushion throughout.
Clean well!

When reassembled this thin plate is the only thing that should move,
it acts as a one way valve allowing oil through easily on the downstroke while on the upstroke it has to pass through the holes in the nut assembly.
The order for reassembly. Dont forget to look in the nut from this side and see how the damper (rebound) adjustment works. The flat sided hole in middle takes the damper adjustment rod that runs from the top. The small and large holes offer the high and low damping levels ( and work progressively at points between them.)

The bottom of the damper tube has the valving for the down stroke.
Those 3 plates are pushed out when the downstroke is strong (big bump) 		The bottom of the damper tube.

When taken out it separates again to show the parts. In this order,
thin ring first on bottom cap then solid ring and then hole ring, with spring last.
On a normal slow or small movement the oil passes through the center hole in center bolt.
When its a sudden or long movement the oil pressure forces the shims under the center bolt to lift, when the stroke returns the oil is controlled by the 3 shims and spring (damped)
This is then further controlled by the assembly previously mentioned in the end of the damper tube. Imagine working all this out!
 

So its time to look at the top cap which houses the adjuster for damping.
The damper adjuster runs through he middle of the damper tube. You
might be having horrors at this point about how to get it all back in the
right spot but, fear not, they are VERY GOOD  at this and it all works
out easily. As you can see the adjuster arm is broken but the other bit is with it and can be easily repaired.
The components of the adjuster are the black toothed wheel, a nylon bush and a
spring plate. The important thing is that the toothed wheel has a flat side on its inner hole that takes the adjuster rod and a thick section on the outside ( the cogs) that goes to the rear of the housing. This locates the wheel in the right place. To put it together, push the spring plate down with a small screwdriver and push the wheel in with a finger. The nylon bush has already been located with a spot of grease to hold it. If you now insert the adjuster rod you can turn it and feel it click from one side to the other, the center ridge on the spring plate works with the groove in the bottom of the wheel. NOW REMEMBER that this top cap has to be screwed on with the adjuster rod in it, MORE later.
Remember I have two shocks. The "old" one had evidently been repaired before.
The method chosen to rebuild it was to machine the damper bush down (bottom) and so allow room for the damper tube to be folded over again.
Note, the bottom one is 83000km top is 20000km, not a lot of difference!
They were meant to last!

So after a bit of thought I asked Well Done Engineering to make up a bush to replace the one within the damper tube, they used some material that I cant remember the name of but which would stop the metal to metal contact and withstand some pressure. I think its important not to leave this out, although road bikes might never use the rebound cushion a dirt bike will and metal to metal is to be avoided. The steel cap that is knocked of the end of the damper tube wont pass the damper bush but is not a very neat fit either so I turned a washer down to make a stop that fits the damper bush and the steel ring (above).

The new rebound cushion in place.
So its all together and (right) its welded up. TIG is fantastic.
The eagle eyed will have noted that the spring holder is not on and it doesnt fit over the steel ring, so i got to try out the idea you could grind these welds off and redo the whole thing. I did, it worked and Paul got to weld it up again. THE OTHER THING IS YOU SHOULD PUT OIL IN THE DAMPER TUBE BEFORE ASSEMBLING. The heat from TIG doesnt cause any problem and its a pain to get it to go in there later (believe me)
In the above right pic you can see the new bottom out cushion that was
sourced from IKON Suspension. They were very helpful and the material is easily shaped to fit your needs. The top cap lock nut (ring) goes to about a turn from the end of thread. The damper adjuster has to fit into the top cap and be inserted in to the damper tube and screwed on (turn it upside down)
Remember that the nut on the bottom of the damper tube has a slotted hole into which the end of this adjuster is going to fit. It has to be already in the slot in the cap. How will this work you ask?. Just screw the cap on and when its still a bit away from the lock ring you will feel a resistance (or you could be lucky) which is the end not fitting with the slot. Back off and try again, gently screwing a little more, back off again if needed but persist (gently). It will line up and screw down fully. Being gentle but firm and feeling the way in is the trick here (like sex?) When you are pushing on the valve plate at the bottom i guess it must stay still and the adjuster keeps turning until one pops through the other. You can practice this before final assembly if you like, I had my doubts but it worked really well.
The adjuster.

Possibly not the best design possible. It was not present at all on either of mine.
The gear wheel is plastic and as mentioned before has a section that is thick which should be faced to the back of the top cap. The arm then screws in to place with the adjustment midspaced.
THIS MUST BE THE WEAKEST LINK in the whole thing, can imagine many are missing. Some units would have been declared "stuffed" because of the gear wheel being turned manually by screwdriver (or whatever) after the arm was broken or some attempt made along this vein. THE REASON: well after getting mine all together and finally getting oil into the damper tube (because i hadnt prefilled it) I found that I had misaligned the arm with the toothed gear by just a tooth or two.  The effect is revealing, I took the shock back out and looked carefully at what was happening. For a start, when you have installed the arm, check its movement to either side by looking at the spring plate under the gear. You should see the plate spring up into the corresponding slot in the bottom of the toothed gear at either extreme. The effect of having the gear and arm out of adjustment by even a single tooth is the complete seizure of the rebound stroke at that extreme point. In other words, if you misalign the gear wheel and the arm it will at one end or the other move beyond its operating range which has the effect of blocking the rebound damper. You push down and the shock doesnt come back up. Move the gear to another position within its range and all becomes well but you have lost a degree of adjustment in the other direction. SO, its very important to get the gear and arm in the right place. And you can tell because when its right you have a very mild damping effect at the light end and a very strong damping effect at the high end.

Left, the seal and spacer as well as the back up ring I ordered from CMSNL.
Didnt need the back up ring and indeed what arrived had been around for a while and took them a while to find (note the old honda logo) (far left)

 

The proof of the  pudding is in the eating as they say and I am personally pleased at having taken the time and trouble to work this out. The shock feels fantastic and to ride the bike is to fall in love even more with it. On low damping and about 10psi air and my weight of 77kg or so the ride is superb. Damping is perfect even on sweeping undulations.
Am a bit staggered at how good it is, can see how the other bike with its standard shock but with no damping adjuster is probably just in need of fresh oil and a lower damping setting. Can also see why anyone riding a bike with damping too high would see it as being hard (some early road test).

Hope this helps some other rider to get their bike back to what was originally intended.
 

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