Ducati Monster Forum

Showa blues
or how to fix your Monster / ST / etc. front spring holders (part 1).

Update February 2018: Having learned a thing or two since this was first written, I will bit by bit update this to make it more up to date. Since these forks are no longer delivered (seems the forks on basic Ducatis are now even worse ...), maybe there is not that big demand for updated info, but since I have it ..... Updates will be posted in yellow.

Kind regards.
Torbjörn.

As they come, the stock Showa adjustable forks used on Monster 900´s, Monster 1000DS (but not the 1000DS Super Sport), ST2/4 etc. (for 50mm / 54 mm triples) are designed in a way that makes it impossible to really affect the compression damping.
 
It took quite a lot of figuring out by myself and a friend and fellow Duc-clubee to figure out what´s wrong with these forks, and work out a solution. By now I have modified quite a few forks utilizing various Öhlins and K-tech shim stack kits, all requiring significant modification to existing parts, and / or manufacture of new parts.

After having had contact with Chris Taylor at K-Tech, there seemed to be a possibility to modify the forks with minimal manufcturing of new parts necessary, using existing K-Tech hardware instead. Only the control rod for the rebound damping need to be fabricated. Access to some workshop equipment is still necessary, however.
 
Modified as described in the following, the Monster / ST style 50 mm / 54 mm forks will generally work as well as any cartridge forks, with maybe a slight focus towards track due to piston lay-out and shim set-up.  
  
Step 1: general disassembly.
Start by turning the spring preload all the way out, loosening the top triple clamp to unload the fork top nut, and break the top nut loose. Then take the fork legs off the bike.
Unscrew the top nut leg, push down the spring / spring preload tube assy and push a slotted washer under the lock nut to keep the spring / preload tube out of the way so you can get at the top nut and locking nut on the cartridge rod.

(https://live.staticflickr.com/65535/48988150447_80a18c9b36_b.jpg) (https://flic.kr/p/2hCV5pz)Fig. 1a (https://flic.kr/p/2hCV5pz) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig.1a:
Spring preload tube,  compressor tool (for the spring), slotted  spacer (for locking the spring pre-load tube below the lock nut), and top nut on top of the cartridge rod.

If you are unsure if you have a "bad" fork or not, compare the top nut with picture 8b.
If the rebound adjuster comes with a long rod attached to it, you have a fork with a "proper" daming circuit lay-out. In this case you will not have to do the mod described here.
Of the 50/54 forks, only the SS1000DS has the "good" rebound lay-out. However, both spring and damping is ridiculously soft. Changing to K-Tech parts can have benefits for track riding, but for the road updated shimming and proper springs will be the best alternative, $ for $. See Showa Blues Part3" for more info.   

Loosen the top nut and unscrew it completely from the rod, and measure how much of the rod sticks up above the locking nut. This dimension is handy to have as a reference, since it will affect the total available fork travel by a few mm. You also need it for determining the length of the rebound control rod; more on this later.
Take out the steel washer, plastic spacer, spring pre-load tube and spring, and lay them somewhere handy.

I recommend you then re-assemble the fork top nut back on the cartridge rod in roughly the position it will eventually sit when it´s all back on the bike, lightly lock it with the counter-nut on the rod, and screw the nut down in the fork tube; NO springs.  
Extend the forks as much as possible, and take a measurement to get the max extended length; I measure from the bottom of the outer fork leg to the top of the fork foot; it´s easily measured and repeatable. Write down the dimension.
Now compress the forks fully, measure in the same place and write down. This gives you the max. possible fork travel in stock form. One leg is enough for this measurement.

Next, use an impact driver to loosen the bottom screw in the lower fork leg (with the compression adjuster)  to get the cartridge out. You´ll need a 19 mm socket with a small outer diameter; some 1/2" sockets are too big.  I use a  3/8" drive socket with a 1/2"by 3/8" drive socket converter.

(https://live.staticflickr.com/65535/48988151027_f82075c44a_b.jpg) (https://flic.kr/p/2hCV5zz)Fig. 1b Bottom plug removal (https://flic.kr/p/2hCV5zz) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig. 1b:
Bottom plug removal.

It may be possible without an impact wrench, but it has never worked for me.
Do the extended / compressed measurement routine once again on the bare cartridge; this will tell you if the fork or the cartridge will bottom out first. Hopefully, the forks will bottom out first. Write down for later reference.
Both these measurements will be sort of base-line measurements, since the cartridge still has the hydraulic travel limiter in place. Removing it might / will change these measurements slightly.

Step 2: Compression stack removal.
Next, go to your drill press and drill out the dimples at the bottom of the cartridge to get the compression stack out.

(https://live.staticflickr.com/65535/48987952911_534c10d1c9_b.jpg) (https://flic.kr/p/2hCU4FM)Fig. 2a Cartridge dimple (https://flic.kr/p/2hCU4FM) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig.2a:
The dimple, and the one opposite, shall be drilled out.
The shiny thing is the compression stack holder.

Just drill through the cartrige wall and a little bit more, It does not matter if you drill al little into the compression stack holder, but don´t overdo it.

Screw the bottom nut a couple of turns back into the compression stack holder  and use a plastic mallet or similiar to tap  the compression stack holder (with stack ..)  far enough into the cartridge so that you can see the lock ring in the groove inside the cartridge tube.
 
(https://live.staticflickr.com/65535/48987953386_4e15a71e7d_b.jpg) (https://flic.kr/p/2hCU4PY)Fig. 2b Comp Stack knock in (https://flic.kr/p/2hCU4PY) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig.2b:
Knock the bottom plug / compression stack holder into the cartridge

Prise the lock ring out; easiest done by pushing the ring opposite the opening down into the cartridge and then just lift by the ends out of the tube.  

(https://live.staticflickr.com/65535/48987953376_a825f411ba_b.jpg) (https://flic.kr/p/2hCU4PN)Fig. 2c Lock ring removal (https://flic.kr/p/2hCU4PN) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig.2c:
Compression stack lock ring.

Getting the compression stack assy out of the cartridge can be tricky; for some reason the last bit always seem to be very tight.

Not wanting to use the cartridge rod to knock the compressions stack out, I used to use the bottom screw / compression adjuster screw and various suitable washers to pull the assy out of the cartridge by screwing the bottom screw into the stack holder against the washers on top of the cartridge until it bottoms in the holder, screwing it out again, add some washers, screw in again etc until you can pull the stack holder out. Now I have an old compression adjuster screw and a sliding hammer contraption to pull it out.

(https://live.staticflickr.com/65535/48987396188_2ee5f2ace4_b.jpg) (https://flic.kr/p/2hCRdc7)Fig. 2d Comp stack holder removal (https://flic.kr/p/2hCRdc7) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig. 2d:
Pull the compression stack holder out of the cartridge
When the stack holder assy comes out, the stack holder might look a bit second hand, but that´s not a problem.  

Step 3: Compression stack conversion:

To convert the compression stack from Showa to K-tech, you need to take the Showa scrapstack off the stack holder. You need a lathe or similiar 3-jaw chuck to hold the shim stack holder or you´ll run a serious risk to deform it, rendering it useless.


(https://live.staticflickr.com/65535/48987395493_32bd5761ed_b.jpg) (https://flic.kr/p/2hCRcZ8)Fig. 3a Cooking LocTite (https://flic.kr/p/2hCRcZ8) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig. 3a:
Use a hot-air gun to heat the stack holder to "sizzle hot" to fry the thread-lock
.
Take out the Showa stuff and throw it away. Or keep it if you like keeping trophies, or nail it to your garage wall. You could use it for target practise or something like that, it´s not very much more usefu for anything.
 
Take the K-Tech stack on its hollow Allen M6 bolt, add a small dab of blue Loctite or similiar to the thread and screw down into the stack holder. Note, a small dab since too much of this stuff will always end up where you don´t want it, like gluing your shim stack solid or do some other nice trick. Torque down to a reasonable feel; take care not to trap and deform the check valve shim.
 When you´ve got this done, the compression stack is finished.

 (https://live.staticflickr.com/65535/48987396123_f474af4c8a_b.jpg) (https://flic.kr/p/2hCRdaZ)Fig. 3b Back Valve Check (https://flic.kr/p/2hCRdaZ) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig. 3b:
This is the way the compression stack should look like when assembled.
You could also take the opportunity to check that the back-flow shim moves easily; this is where the oil goes to re-fill the cartridge on the return stroke.

(https://live.staticflickr.com/65535/48987396133_f2e2374ec9_b.jpg) (https://flic.kr/p/2hCRdba)Fig. 3c Comp Stack Comparo (https://flic.kr/p/2hCRdba) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig. 3c:

Stock compression stack on top, K-tech version below.
Note the mangled lock-ring ridge on the top one, that´s how it came out of my forks the first time I took it apart.  


Step 4: Rebound stack conversion
You now need to get the rebound stack out; it´s at the end of the cartridge rod inside the cartridge. To get the rod out of the cartridge, first prise out the top lock ring above the white plastic cone on the rod, push off the cone (actually part of the hydraulic travel limiter assy), prise out the bottom lock ring as well and push the cartridge rod down out of the cartridge.  

(https://live.staticflickr.com/65535/48987952831_9db83d15e4_b.jpg) (https://flic.kr/p/2hCU4Ep)Fig. 4a Hydrostop removal (https://flic.kr/p/2hCU4Ep) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
Fig. 4a:
This is the hydraulic travel stop; I throw them away. The SBK forks I´ve worked on do not have them but I think they have some kind of soft washer under the top nut. My Öhlins R&T fork has neither.

Next up is the rebound modification, where you´ll need to remove the stock shim stack holder from the damper rod, and replace with the K-tech part.

Start by drilling through the dimples in the rod that keeps the holder from turning in the rod.


(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig4bReboundstackremoval.jpg)
Fig.4b:
Drill out the dimples.....

Heat the shim stack holder / rod end area with a hot-air gun until it is sizzling hot; this is (again) done to destroy the thread-lock agent put there by Showa. Failure to do any of these steps might lead to destroyed threads in the rod end, causing quite a bit of unnecessary work.
 
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig4cLocTitecooking.jpg)
Fig 4c:
Just a some more hot air ...

Clamp the rod in a 3-jaw chuck or similiar and screw out the shim stack holder.
The rods I´ve done don´t have the internal thread all way down to the end, and after you´ve drilled out the dimples there likely will be some burrs that might cause the K-tech stack holder to cross-thread on the threads proper and end up mis-aligned with the rod.
Ideally, a 7.2 mm drill bit would clean this out without removing too much wall thickness. However, a 7.5 will do, but don´t feed any further than necessary since the K-tech holder has a shorter thread than the stock holder and you want to use all the thread you can. You could also machine off the bottom of the rod to get rid of the "bad" part


(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig4dReboundholdercomparo.jpg)
Fig. 4d:
Different rebound stack holders, r-to l: Stock; K-Tech for 10 mm cartridge rods; K-tech for 12 mm rods, and K-tech for 10 mm rods with external thread.  

For this conversion we´ll use #2 from the right.


(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig4eCartridgerodtop.jpg)
Fig 4e:
Cartridge rod with stock rebound damping orifice still in place.....
.... and with the orifice removed and rod end cleaned up.

Before assembling the shim stack holder, you need to fix the top end of the cartridge rod: screw out the orifice, and clean out the end of the rod so it is reasonably smooth and burr-free.
After you have done all the modifications to the rod, clean it out with solvent and compressed air and make sure all the burrs and stuff is cleaned out.

Assemble the complete K-tech rebound stack holder with shims and all on the rod, again using a small drop of LocTite on the threads and a 3-jaw chuck or similiar to hold the rod, and tighten "properly".

 
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig4fRodswithrebstackscomparo.jpg)
Fig. 4f:
Stock rebound shim stack (top) and K-Tech
stack (bottom)


Before putting everything back into the cartridge, make sure the cartridge tube is free from burrs and similiar after the drill-out operation.
Edit Feb 2018: I now use a Dremel for this, before pulling out the comp assy, rounding all the holes inner edges to save the O-ring. I also do it before pulling the base balve out first time to save the O-ring. If you do this mod, you don´t need the O-ring, but since it´s an odd size, you never know ...
 
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig4gCartridgedressing.jpg)
Fig. 4g:
Clean out any burrs before you push in the cartridge rod with rebound piston.

Step 5a: Lock ring up-grade.
This is an optional extra. if you don´t want to do this, just proceed to step 6.
On one or two forks I´ve worked on, the compression stack holder had moved on the lock ring, making it look pretty ugly and like it could work loose eventually (see the picture of the 2 compresion stack holder).

The stock lock ring is only 1 mm diameter wire, and a little heavier gauge lock ring would do niceley here. It took a while before I found a suitable one, since next step is usually a 1.5 mm wire ring which is far too much.
However, eventually I found that JE piston pin rings were 1.27 mm diameter (probably 0.05"), and are available in 20 mm, and fit this purpose perfectly.
Part number is 787-050-MW, or at least that´s what it says on the plastic bag it comes in, and it will fit perfectly in the cartridge groove.
Please note, the lower end of the compression stack holder won´t go through now, so you´ll need to slightly reduce the lower diameter of the stack holder (about 0.10 mm or so) to suit. I put  the ring in the groove in the cartridge tube and measure, then test with the tube + ring, machining very small increments to arrive at a tight fit.

 If you do this, the whole setup will be much sturdier. On full extension, this lock ring holds the whole fork leg from falling apart, so I like the feeling of knowing it´s a bit more robust. If you don´t feel like going through this extra work, just skip it.  

Step 5b: Fork leg surface dressing.
This is another optional extra. If you have the lower fork leg separate, you could now dress the surface of the lower leg to get rid of any polished areas and get a nice criss-cross pattern. Use a  fine wet-grind paper maybe 1200 fine, some light oil as a cutting oil, and take care that the brake caliper hangers does not get your fingers.
Edit Nov. 2018: There are different views on what grit to use; I don´t know if there´s a "correct" grit. I now often use coarser than 1200, you´ll have to decide for yourself ...

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig5aLowerlegdressing.jpg)
Fig. 5b: You certainly need a lathe to do this
If you have the TiN-coated legs, DON´T do this.

Step 5c: Rebound oil leak sealing.
The final optional; since the stock cartridge rod is used in this conversion, the two holes that lead oil from the cartridge to the top nut rebound adjuster needle in stock configuration are still there, as are the holes in the top nut leaking the oil back into the fork leg (see picture).
You can use set-screws in the top nut,sealing these holes off. In this way, all the oil has to pass trough the compression andjuster and/ or shimstack on th ecompression stroke.
I´m not sure if it makes a noticeable difference or not. In theory it does, and it is not a whole lot of trouble so I usually do this.
Edit Nov. 2018: I now just do the O-ring on the control rod. Just make sure it´s above the entrance holes in the cartridge rod.  

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig5cOilleaker.jpg)
Fig. 5c:
Leak holes in the top nut. The holes are about 3 mm in diameter. Get a 3.2 mm drill bit, cut an M4 thread,  and loc-tite M4 set screws in place.
You should be able to find them in any shop supplying screws and such. Again, buy something else at the same time, they are embarassingly cheap.  


Step 6: Cartridge re-assembly.
Now you´re ready to start assembling the forks. Lubricate the rebound piston seal ring and rod, and push up through the cartridge.

Screw the compression adjuster screw into the bottom of the compression stack holder, lubricate the seal ring, and carefully tap the compression stack holder / shim stack assy into the cartridge tube far enought to enable you to assemble the locking ring in its groove, screw out the adjuster screw / assembly tool, assemble the ring, screw in the fork bottom screw again and carefully pull the compression stack holder back out until it bottoms squarely on the lock ring.
Edit Nov. 2018: Before you do this, it´s very important that all the holes in the cartridge have been de-burred / rounded, so the O-ring will not be damaged.

Now is the time to measure cartridge stroke again and compare with the cartridge stroke as measured in section 1. Assuming you have thrown the travel limiter away, when the cartridge bottoms out it will be the shim stack holders meeting, so be careful.

End of part 1.

nice writeup!

Showa blues
or how to fix your Monster / ST / etc. front spring holders (part 2).

Please go back to part 1 for the previous steps.

Step 7: Cartridge re-assembly into the fork.  
Put the cartridge back into the fork (with the bottom locating washer / cartridge seat in place),


(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig6aCartridgewbasewasher.jpg)
Fig. 7a:
Don´t  forget to put the cartridge seat back on top of the cartridge before assembly in the fork.  

put a new copper seal ring on the bottom screw, put some thread lubricating compound on the thread (do NOT use LocTite, or you´ll never be able to disassemble this again), and tighten in a few steps to 35 Nm.

Step 8: Rebound adjuster modification.
This is an optional extra, but it is probably a more robust solution to machine the rebound "needle" off the brass adjuster screw in the top nut. I have done some with the needle left, and some with the needle machined off, don´t really know if it matters.
I´ve also seen a few different "needle" designs, so if you machne the tip off, the removed length might be a bit different depending on what needle you happen to have.

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig8aAdjusterremoval.jpg)
Fig. 8a:
To machine the adjuster, you obviously have to remove it from the top nut; just screw it out until it comes out.
After a while (about 35 clicks from full out) you will run out of clicks; just go on until you can push the needle out.Sometimes, the  little spring-backed ball responsible for the clicks will drop out, but surprisingly often it stays put.
If it does drop out, peek into the top nut from the bottom. Just above the last thread you´ll see a small hole. Put a dab of grease on a small screwdriver to hold the ball and carefully put it back in the small bore.

 
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig8bTopnutdissassembled.jpg)
Fig. 8b:
Top nut (with spring pre-loader removed), "click" ball, adjuster screw with needle.
 
If you´d happen to lose the ball, don´t worry; you can get new ones at your bearing store. For some reason Showa has decided to use inch-sized balls, the ones I´ve checked were 1/8". If you do need them, buy something else at the same time; they are embarassingly cheap.
 
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig8cAdjustercomparo.jpg)
Fig. 8c:
Standard and machined adjuster screw. The tip is 8 mm long on this one.


Step 9: Rebound damping adjuster rod.
When you use a K-tech kit you do not need to manufacture any needles; you use the stock compression needle in the bottom plug, and the rebound needle comes with the kit. However, you have to manufacture an aluminium rod to control the rebound needle. To do this you must establish the proper length of this rod. Since the working space of the needle return spring is about 3 mm, you have to get this reasonably right, or you´ll miss the working range of the adjustment.

Take the needle with the spring, and drop it down the cartridge rod.

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig9aRebneedleassembly.jpg)
Fig. 9a:
This kit comes with this needle (no O-ring); it will drop right down the rod (or out of .... ).

Others I´ve seen come with an O-ring on the needle, this means you have to push the needle down the rod until it bottoms out.
Next, take a 5 mm diameter aluminium rod and push it down the tube and make a mark on the alu rod at the top of the cartridge rod. You want this to be to the closed position of the needle, so slightly press on the rod against the return spring of the needle until you can fell the needle stop against the seat.
Then, pull it out and measure the length.

Then take the fork top nut, back the adjuster screw all the way OUT, then screw it in again,counting the clicks until you run out of clicks; screw it back a little until you have distinct clicks again and note how many clicks you have.
You might have to do this a couple of times in order to make sure you´ve got it right. You will probably end up at around 35, and I usually set it at 25-26 clicks.

Measure the distance from the bottom surface of the top nut up to the tip of the brass adjuster screw, this distance beeing "a".
 
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig9bTopnutdistance.jpg)
Fig. 9b:
Measure the distance to the adjuster needle in top nut; this is the distance "a".


Next, measure the lenght of cartridge rod above the lock nut, distance "b".

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig9cRodtopdistance.jpg)
Fig. 9c:
Measure the part of the rod above the lock nut; this is the distance "b".

By deducting "b" from "a" you´ll get the amount of control rod that shall protrude above the cartridge rod end in order to get a working rebound adjuster.
 
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig9dCartridgerodwcontrolrod.jpg)
Fig. 9d:
This is about what it will look like if you have machined off the needle tip of the adjuster screw.

Edit 2013-01-25
The current .... SHO13 kit has a longer rebound needle than the one you see in the picture above:

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/P2020014_zps5151ace7.jpg)
Fig.9d: Some different K-Tech rebound needles. The current ...SHO13 kit needle is the one on top.

With the ... SHO13 kit needle, the adjuster rod will look like this (picture 9d1 and 9d2):

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Cartridgeandadjusterrod1copy.jpg)
Fig. 9d1:
If you put the cartridge rod and adjuster rod along each other like this........

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Cartridgeandadjusterrod2copy.jpg)
Fig. 9d2:
..... the adjuster rod should be appr. 41 mm shorter than the cartrige rod (still woth the brass needle tip machined off)

End edit 2013-1-25

Edit 2013-02-27:

Also, I´ve added an O-ring on the control rod:

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/P2230009_zpsd7077528.jpg)

Edit: O-ring 6x4x1 mm, groove dia 4.2 mm.
The groove is square in profile, to keep the O-ring in.

End Edit.  

Leave the needle tip and the control rod will be roughly flush with the cartridge rod.

You should do this pretty carefully so that you get close; minor adjustments can be done by screwing the lock nut up or down slightly on the cartridge rod.

To test if you´ve got it right, make sure the needle is still in the cartridge rod,  drop the control rod down on top of the needle, position the adjuster in the top nut in the screwed-in position used when taking the dimension "a" as mentioned above, i.e.8 to 10 clicks back from "no clicks".
Carefully screw the top nut down on the cartridge rod until the adjuster screw makes contact with the control rod; carefully screw it further down until the rebound needle bottoms and the nut won´t go down further.
In this position there should be some clearance between the bottom of the top nut and the lock nut. If not, your control rod is too short and you´ll have to make a new, slightly longer one.

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig9etopnutlocknutpos.jpg)
Fig. 9e:
With the rebound adjuster in the "in" position (i.e., where the adjuster should be closed) and the needle seated against its seat (i.e., fully closed rebound adjuster), you should see some air between the top nut and lock nut
When you have this sorted, I recommend you lightly lock the top nut in place with the lock nut, screw down the top nut in the fork leg, and do the extended / compressed routine again, taking down the dimensions.  Presumably, the forks should bottom first, which in that case will now mean that the lower fork legs will bottom out against the bottom of the fork top nut.
Anyway, compare the fork stroke with the bare cartridge stroke; as long as the cartridge stroke is greater than the fork stroke, you are safe.
If not, go back, find the reason, compensate and proceed. Quickly said, but quite a lot of work, really.

Step 10: Fork re-assembly.
Next, screw off the top nut again,  pour in some fork oil, either Öhlins R&T fork oil, or 5W fork oil of any known brand, and start working the cartridge up and down to get oil into the cartridge. Using a hose with a couple of holes in it will help you catch the cartridge rod down in the fork leg, and keep the oil under slightly better control. There will be oil most everywhere anyway when you are finished, but in this case less is better.

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig10aCartridgedeaerating.jpg)
Fig. 10a:
Work slowly, or you´ll have oil all over the place ....

In the end, you´ll probably have oil all over the place anyway, but trying to be neat helps.

If the oil will not enter the cartridge, you have probably put the shim stack on the compression stack holder up-side-down (been there, done that ...). Pour out the oil, disassemble the cartridge from the fork, dissasemble the compression stack and correct. Have fun.  

Pour in more oil, work the cartridge rod, and start measuring oil level. I usually start at 120 mm from the fork tube top with the fork fully compressed and no springs etc.; you might have other preferences. Keep it reasonable, a few mm this way or that might matter to Casey Stoner, but certainly not for me and probably not for you, but it´s your choice. If you decide on less air, make sure your forks will not lock due to oil overfill.

When the oil level is done, drop in the spring, spacer and associated hardware, and lock the spring under the lock nut with the grooved spacer described before.
Assemble the top nut as desribed in section 9, but after you´ve bottomed out the rebound needle, tighten the lock nut gently against the top nut, back off the adjuster a couple of clicks to protect the rebound needle, and tighten the lock nut against the top nut.
Remove the grooved spacer, make sure the spring spacer etc. are correctly positioned, and screw down the top nut in the top fork leg.


If you like, you could now do a "bump test": Screw both adjusters all the way out, and heave on the fork. It should pretty much pogo in and out with little resistance. Close the compression adjuster at the bottom of the leg and do the same; there should be a marked increase in resistance to compressing the forks. Now close the rebound, the return stroke should be real slow.  

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig10bBumptest.jpg)
Fig. 10b:Bump test.
If you make a handle like his one, you can  test various settings on your stock forks, and feel for any difference in compression or rebound damping.

On a standard fork, with the rebound damping even only slightly open, you will not feel very much difference at all in resistance when compressing the fork, no matter what the compression adjuster is set at.
 
Then do the same after you have modified your forks, and notice the difference: No matter where the rebound adjuster is set, there will be a noticeable difference in compression resistance with different settings of the compression adjuster.


Put the fork tubes back in the triples, tighten the lower clamp bolts to 15 Nm, tighten the top nut, and last tighten top triple to 15 Nm.

With everything in place, you can test the damping: Spring preload fully out, compression damping fully out, rebound adjuster fully out. Pull the brake lever and push down as hard as you can on the forks and let go. On rebound, the forks should lightly top out and sink back a little bit. Screw down the adjusters one or two clicks at the time until this happens. This is a good starting setting for the rebound damping.
 
Then set the compression adjusters 10 or so clicks out, put a tie-wrap around one of the forks legs (I prefer the right leg for convenience with the bike on the side stand), and push it up against the dust seal.You use this to evaluate spring preload and compression damping settings later after you have ridden the bike.

Set the sag to some sensible value, don your riding gear and take a ride, enjoying your immensely improved front suspension. Play with the adjusters until you think it feels right when going over bumps, braking (tie-wrap!) or whatever riding condition you think is important.
I always approach suspension settings from the soft side on all adjusters, working up to what I feel is right. This will take some time, but is well worth the effort; this whole modification is wasted if you don´t take the hassle to get the settings well sorted for whatever riding you do.

This might sound like a lot of work, and that´s because it is. However, if you plan on taking your forks apart for any reason, like a seal change, it´s not really that much more work. If you plan on doing a re-valve job anyway, only the manufacture of the alu rod is extra. You will have much improved suspension, and effective adjusters.
Just putting in a Racetech Gold Valve will not help (been there, done that ...), you have to do the modification to the rebound damping circuit to get an improvement.

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/KompmojmedRaceTech.jpg)
Fig. 10c:
Racetech Gold Valve.Not much change, but it was before I knew ...
 
 You can also revel in the fact that you now have made a moderately expensive performance conversion that actually works but is invisible, as opposed to a lot of carbon fibre and such which is moderately to very expensive, very visible but makes no performance difference whatsoever  :-) Well, in most cases anyway.
There is also the risk this mod will incur further cost; when you realize how nice good suspension is, you´ll probably want an Öhlins shock absorber as well pretty soon!
Tools needed:
•   6 mm allen key or socket for the triple clamp bolts;
•   22 mm socket for the spring preload;
•   32 mm wrench for the top nut;
•   Spring compressor tool to compress the spring; not essential but very helpful;
•   Slotted washer to keep the spring down;
•   14 mm and 17 mm wrench for the top nut and the lock nut;
•   19 mm socket with small outside diameter for the bottom plug
•   Impact driver, also for the bottom plug,  
•   Piece of hose to help fishing up the cartridge rod when the spring, spring preload tube tec. are in place is very handy.

Disclaimer.
The modification outlined here is not the easiest and should not be attempted if you do not have the necessary skills and tools. I can´t say I had either when I started taking my forks apart, but in case of a screw-up I´d had no-one to blame but myself.
This how-to is written with the best intentions. Based on my own experiences and mistakes, it reflects the best of my knowledge, and I´ve tried to anticipate any problems you might encounter along the way accordingly. "Anticipate" in this case pretty much beeing an eufemism for "experiencing", actually, when I come to think about it.

However, I don´t expect it to be foolproof (you know how ingenious they can be ...), and you have to use your own judgement. If you do not feel up to the job, contact a reputable bike shop to do the job. If you do it yourself, you do it on your own responsibility, and if you screw up, it´s also on your own responsibility.  

I also have to mention I have not actually ridden a bike with a fork modified as per this description. I have, however, ridden bikes with similar K-Tech mods, only using slightly different parts, and I have two bikes (OK, one and a half) with the first version mod using parts produced locally and Öhlins shim kits. They have all worked very well. No guarantee, sure, but an indication, I believe. Also, the bump test indicated the same result as previous modifications; at least a further indication.

Parts.
The K-tech parts used here are bits and pieces for various applications, the all-important rebound stack holder I think is for a "CR85/150 MX bike". I don´t know if that says something about Ducatis view of us Monster riders, sending suspension of this grade our way, but that´s what it is.

The parts needed are now available as a kit from K-Tech with the part number 20SSK-INT-SHO-13. Right now it contains the complete rebound stack with needle and spring, the complete compression stack with suitable, hollow M6 bolt. This means you have to use the stock compression stack holder.
Later, it will probably contain the the compression stack holder as well, so the kit will then be: rebound shim stack complete as a set on its holder with adjuster needle, and compression shim stack complete mounted on a new compression stack holder.
Edit: As far as I know, the kit does NOT include the compression valve holder.

You will then just have to:

• Dissasemble the cartridge;
• Throw out the compression stack with holder and substitute for the new part;
• Take out the stock rebound piston as outlined in section 4;
• Replace with the new rebound stack assy, also in in section 4;
• Manufacture a new control rod as per section 9;
• Assemble the whole caboodle as per section 6, 7, and 10.

Unfortunately, Showa has several different combinations of fork leg, cartridge, and cartridge rod lengths out there. Therefore complete kits with rods and everything cannot be supplied as a default solution. Some probably could already now; you´d have to check with K-Tech.

As the database grows, I´m sure more and more models will be added to a list of complete kits.
Presumably, you could also order complete kits from K-tech by taking your forks apart, take out the cartridge rod, measure from the top down to the rebound piston flange and inform K-tec0 If you do so, be careful to also state bike model and model year so that the database can be made more and more complete with time.

I´m sure, they can also do the whole mod for you if you send them your cartridges. This might be more or less practicable depending on where you live. Contact K-Tech at www.k-tech.uk.com (http://) (http://) (http://) (http://) (http://) (http://) (http://) (http://) (http://) for further details on parts and partners.
For those of you living in the US, there is a US disributor:

Orient Express
28 Grand Boulvard North
Brentwood
New York
11717
+1(6312) 319 552
skip@orientexpress.com

Legal aspects and disclaimer.   
Since we are very obviously dealing with safety-related parts and modifications here, and with the sue-for-money-if-you-can-or-even-if-you-really-couldn´t mentality rampant, I´m not sure if you can order the K-Tech parts yourself, or if you have to order them thru a dealer / retailer, or if you have to get the job done by a K-tech autorized bike shop. Check for a K-tech dealer close to you, and start the discussion with them.
I´m sure there are aspects of this job I have not thought about. If you set out to do this modification, you do it on your own responsibility and you have to use your own judgement and experience to make sure the job is done properly.
That said, if done properly I´m sure you will be very happy with the results.

Holy crap! Now I know why I pay guys like you to do this stuff for me!  [bow_down]

Nice tutorial!

Thanks, glad you enjoyed it.
It was my intention to be thorough in order to make it simple for anyone wanting to improve on their front suspension without having to adapt some other forks.
I´m starting to wonder if I´ve scared people off instead ... ???

Anyway, it really is quite basic. Just let it take the time it takes, and nothing much can go wrong. It´s definitely worth the trouble and expense.

I am really glad you are sharing your efforts to fellow ducatisti and respect your persistence in finding a solution for the problem with monster forks!

I am definitely going to do this mod on my ss900 forks!. I have once installed Bitubo valves to some S4R forks and wondered too why the compression adjuster doens't seem to have any effect. I never was really satisfied with the damping of the forks even after the mod.

However there is one thing that caught my attention on this mod.

If there is no O-ring on the rebound adjuster needle, won't the oil still be able to escape upwards through the damper rod? Even if you seal the holes at the fork cap, this leaves air in the upper part of the damper rod and this air would compress when the pressure inside the cartridge gets high during the compression stroke and let some oil escape from the cartridge. The amount of oil would be low but so is the amount of oil flow through the compression valve. Of course this escaped oil would return to the cartridge afterwards, but i suspect that completely sealing the lower end of the rod could give a more solid damping action.

So I would be interested if you can find out if the needle with the O-ring you had in the pictures from the previous instructions is compatible with this mod (if it would seal against the stock damper rod) and if you could also give us the part number for the o-ringed needle.

Edit:
This is the pic of the needles I mean
http://www.ducatimonsterforum.org/index.php?topic=50161.msg939124#msg939124 (http://www.ducatimonsterforum.org/index.php?topic=50161.msg939124#msg939124)

On a second thought, maybe the o-ring in the needle would not be so good idea. As the oil can flow freely through the body of the rebound valve during compression stroke, the full damping force is acting through the small area of the damping rod on the fluid inside the cartridge. This high pressure would cause an enormous force on the rebound needle if it was sealed against the damper rod (If the rod diameter is 10mm and the inside diameter 6mm, it would be 36% of the total compression damping force). This force might be enough to permanently deform the slim 5mm aluminum rod and cause the rebound needle to lose its setting. And it would transmit a considerable force to the threads on the stock rebound adjuster.

Another thing coming to my mind is that the weight of the 5mm rod will be resting on the small spring of the rebound needle. Is the spring stiff enough to keep the needle from banging against the rebound valve holder in sharper bumps? If not, I would probably try to attach the 5mm aluminum rod to the rebound adjuster at the fork cap. They could probably be quite easily joined by making threads to both.

Edit: Ok, I'm slowly starting to comprehend the whole workings of the forks. Even if there was an O-ring on the needle, the pressure would still be passed to the inside of the damper rod by the two small holes at the lower end and this pressure would then exert a force on the adjuster screw at the cap directly. So there is really no easy means to prevent this from happening. If there has been no damage to the rebound adjusters of any of the forks you have already modified, this is probably not an issue.

I would still be worried about the oil inside the cartridge having an escape route through the two holes at the lower end of the rod and then through the fork cap holes if you dont seal them and whether the needle spring will be stiff enough to support the aluminum rod in bigger bumps.

Pajazo,
your thinking is along the same lines as my own, and the kit me and my partner first made had the rod threaded to the needle at one end, and to the adjuster screw at the other end, and an O-ring to seal the whole thing (and provide som cusioning):

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Returnlcopy.jpg)

I´ve also been worried about the design using a "loose" needle to seal an orifice with very varying flow that would tend to blow/suck the needle up and down, possibly creating wear at the seat etc. I don´t  know if this could be a problem, but all the K-Tech kits are like that; I also believe the 888 forks were like that, for instance. The Duc 848 and 1000DS Supersport forks have "solid" needles so both systems are around.  I suppose only time can tell, but I believe K-tech and other would not do it this way if it were a problem.

I do not think that the weight of the alu rod is a problem, the hydraulic forces acting on the needle should be magnitudes bigger.
Sorry, got this a bit unclear: The hydraulic forces and the weight of the rod would act in the same direction when the needle / orifice is active (on the rebound stroke). I´ll see if I can get a view on this from K-tech.

From an engineering "neatness" viewpoint, I would prefer the "solid" adjuster / rod / needle combo, but then I´d be back att making all the parts myself. Lazyness, maybe  :-\

Of course, there is room for improvement here, by making a rod that is threaded to the adjuster screw and has an O-ring groove somewhere just above the "access holes" in the cartridge rod.

Part reason for using the 5 mm rod inside the 6 mm inside of the cartridge rod is to create a very long and narrow path with a lot of friction for the damping oil, but sealing the holes will of course provide a positive seal.
When summer arrives here, I will ask the owner of the forks in the how-to to test first as is, then we´ll put in the sealing screws and see if that affects the settings.
Doing just the bump test as-is (fork caps holes open), there is a definite reaction to compression adjuster setting even with the rebound fully open. At least better than stock, but maybe not as good as it could be.....  

Well, 1 each "I think", "I suppose", "don´t know", and 2 "I believe"... not much in the way of clear answers here ... :-[ . Hope there´s some help in there at least to help your thinking along.        

thanks for getting all that down in one place.  Forks are the one area of my bike which really disappoints me.  Not very confidence inspiring in corners, harsh, /sigh.

When I can find someone to do this that won't crush my bank account, i'll let you know how it goes.

A very simple solution to the design flaw of these forks would be closing the rebound adjuster completely and drilling a small hole through the rebound valve (or check valve shim) to compensate. Then there would be no leakage through the damper rod but we would lose the slow speed rebound adjustment. Getting the hole size right would likely require some experimenting.

Another possible mod coming to my mind would be to transplant upper caps and cartridges from srad 750 forks. The top triple clamp diameter is the same and the top cap thread looks similar and based on information I found on internet forums (very reliable :) the fork lenght is the same on both bikes (730mm) so it is possible that the cartridge length would be suitable too. As far as I know the gsx-r dont have a similar design flaw as the ducati forks. I'm not sure if the thread on the bottom of the cartridge is the same but swapping the compression stack holder would solve that.
I have ridden my brother's srad 750 and liked the forks even with stock valving.

As you have concluded, there are many ways toimprove on the function of these forks; however any method that does not involve changeing shim stacks would leave you with the stock compression shim stack, which is not really a shim stack at all but rather a sort of blow-off valve. I have no idea how it would copw with suddenly having to handle the oil flow previously leaked out thru the rebound circuit. Also, the rebound shim stack is as far in in the fork as you can get, making change-and-test a very laborious proposition.

I´m sure there are other Showa forks on the market where the internals would transplant, and would be an improvement on the Monster Showas. If you find one,  let us know.   

maybe I missed it...

does this part:

Get replaced by this part in the K-Tech kit?


(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/Fig9aRebneedleassembly.jpg)

No, the first part is a needle fabricated for an earlier mod by monsterhpd. The second part is a k-tech needle that is one of the parts  used in this mod.

Monsterhpd: to get to the rebound valve and shims to drill the hole would require the forks to be completely taken apart, so if I would do that, I would of course also change the valving to something better. I only suggested it because it would not be necessary to make any diy parts.

I will probably see if I can find some cheap srad internals to try if they will fit. If I do, I'll report the results.

Correct, two versions of the same part.

Send me a mail and I´ll give you a list of cartridge dimensions (very incomplete, but still ....).

BTW, maybe I missed that, but what is srad?  

Edit:
I asked Chris at K-tech about the questions concerning the "loose" adjuster rod; they´ve been doing it like this for years with no known problems.
As mentioned, my Öhlins fork is also like this as are several others. I woul not expect it to be a problem.

ok, that's what I thought.  thanks.

Do you mean that the öhlins and k-tech use a "loose" rod resting on the needle like in you mod? Then I believe it's not a problem. It is on the sprung side of the suspension too, so I guess it is quite safe to use. I have no idea how stiff the needle spring is but the upward acceleration is probably not very great on bumps so if the spring is stiff enough it should be ok.

Srad means suzuki ram air direct but is usually used to mean the 1996-1999 generation of gsx-r.

Yes, that´s correct. My Öhlins uses the same system with maybe a 3 mm rod instead. K-tech has used the same system for years with no issues, and Kayaba forks are (reportedly) like that also. I do not think it is an issue.

it is probably a slightly more elegant solution to use a slightly thinner control rod, and seal the drainage holes in the top nut insted. I used the 5 mm rod in order to skimp on the top nut sealing.... suppose the lazy streak will manifest itself given just the slightest opportunity  [roll]

Srad, OK, thanks, then I know what you are talking about.

Just as "collateral information"; I had the opportunity to look at a dissasembled fork from (I think) a 1993 900 Supersport. The fork looks slightly different wit the compression adjuster behind the fork legs, but the basic internals lookef just the same with the tell-tale orifice atthe top of the damper rod, and the "short" adjuster needle. Seems Ducati has used this system for a very long time.

Well,
the dedicated kit for the 50/54 mm "adjustable" Showas on Monsters, 900SS/SSie, ST4, etc...  is here.

Part number is 20SSK-INT-SHO-13, and you should be able to order it from K-Tech or their dealers. I don´t know the price of the kit, but if you install it I think you´ll be happy with the results.

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/DSC_0125.jpg)

I disassembled the forks of my 95 superlight yesterday.

The fork bottom bolts came out easily without a rattle gun when the fork caps were still in place.

The rebound holders were incredibly tight and I could not clamp the damper rods tightly enough to undo the threads. Today made a trip to a hardware store to get a heat gun and after generous heating the stacks came off easily. The thread lock Showa uses seems to be really tough stuff. The heat gun is a must in this job.

I also improvised a wooden holder which worked very well for clamping the rods without scratching them. I made small grooves to two wooden blocks with a saw and then pressed them together in a vise. Then using the pre-cut grooves as a guide, I drilled a hole throught the blocks first with a smaller bit and after that a 8mm bit (the rod diameter is 10mm).

(https://lh4.googleusercontent.com/-_6wj3wfW3Sk/T4fOMan74VI/AAAAAAAABZU/byQh76r4nng/s912/IMG_20120413_093949.jpg)

(https://lh5.googleusercontent.com/-snbVipcmL98/T4fOJ6gWSfI/AAAAAAAABZM/R0tNB1bMKx4/s912/IMG_20120413_094008.jpg)
(https://lh3.googleusercontent.com/-izfYj9tBp78/T4fOGC5_YNI/AAAAAAAABZE/UwFDF-xwgTI/s720/IMG_20120413_094040.jpg)

This way it was easy to grip the rod tightly enough to undo the rebound holders without needing a lathe chuck. I will get the k-tech parts today so i will continue later.

Hi,
nice work, all experiences are very valuable for anyone doing this mod (and for me).

I´ve had a report that there has been a problem with assembling th erebound stack holder into the stock cartrige rod. I´m not sure about the exact details yet, but it could be due to the condition mentioned in section 4 of the tutorial, between pictures 4c and 4d.

Clean out the unthreaded portion of the rod properly, and make sure the holder is entering the thread correctly.   

I got the forks together today and have had a short test ride (although in wet weather, and still tweaking the settings) but the impression so far is good.

I had some difficulties fitting the kit because the threading of the lower end of the damper rod to which the rebound stack holder attaches was not exactly straight (even the stock rebound stack holders were a little tilted to side) and that caused the needles to bind in between the rod and holder so they wouldn't return when pressed shut. I got around the problem by cutting the thick section in half and machining some metal away from the lower part (see pic). The upper cut off part must be used to seal the inside of the rod. I didn't seal the holes at the fork cap at all because the thick part of the adjuster needle fitted so closely inside the damper rod that i couldn't feel any air passing when i tried to blow past it.

Apparently this problem is caused by the poor machining tolerance of the stock rod.

(https://lh4.googleusercontent.com/-6sswzkmwmzQ/T4lnwYqdE7I/AAAAAAAABZ4/u9NsPtYIjVo/s284/needle.jpg)

Thanks for sharing your experiences. This is the first time I hear of cocked threads in the cartridge rod, very good you found a solution.

I hope anyone doing this mod and experience a problem / find a solution / find an improvement will post here for the benefit of us all.

Today I had a 250km ride trough a lot of twisties and had an opportunity to try different adjustments to the forks. I have now 30mm sag, rebound 1 turn out and comp 1 2/3 turn out and I really like how the front end feels. I'm still going to try a little bit less preload for the next ride.

Hi, all.

I checked with Chris Taylor at K-tech; seems apart from Pajezo only the kits I´ve flogged have been sold. I don´t want to sound like a K-tech sales rep, but compared to a set of better forks from another bike, this kit is really not a lot of trouble or cost.
Really nobody going to try this...?   

it's on my list, but I'll admit I'm pretty intimidated.

So was I the first time I disobeyed the Duc workshop warning "do not disassemble the cartridge", but in the end it worked out OK. So, be respectful, or whatever the correct english word might be, but don´t be intimidated. It´s not bad enough for that  ;) 

it's not that so much as the vast array of recommend tools I don't have.  Which means I'd have to pay someone to do it which makes it even more expensive.

Well, maybe I´ve gotten a bit spoiled by having access to to basic workshop machinery  :-[

Anyway, the first time I did this I had the following:
The spring compressor handle, which a friend made for me. You need something like this, but it does not have to be professional standard;
The slotted washer to keep the spring down while loosening the top nut;
Impact wrench to loosen the bottom screw / compression adjuster. One Duc club member who did this mod used a long handle and a hammer I think and it worked for him even though I never tried that.
Drill press of some kind to drill out the dimples;
Hot air gun to fry any thread locking compund; I suppose this could be done by baking them in the oven.
A 3-jaw chuck is nice, but a slotted wood block or Alu block to hold the piston rod in a vise while working on the rebound piston holder also works OK.
I suppose a torque wrench for tightening the bottom screw/compression adjuster is not ultimately necessary, but working on bikes one should really have one anyway.

Of course it depends on what circumstances one has; living in a house with a garage (that did not see a car inside in at least 15 years  ;D ) I have most tools except workshop machines, when I lived in an apartment I did not and I´d have had a problem as well.

I think that was it. All deburring I made with a fine-grade rat-tail file and emery cloth, and all washing was with solvent and without compressed air since I did not have a compressor at the time.

I don´t know if this helps any, but in the end the whole thing is pretty basic, really. 

Hi,
Please see below how a Showa Blues modified forks looks like mounted on a Monster  ;)
No need for a Öhlins front end.
By far one of the least expensive performance mod on the bike.
The winter is long so start order the K-Tech kit and begin to diasamble the forks.
/Henrik

(http://user.tninet.se/~cmf606a/ducati/bilder/showablues.jpg)

Hi.

I have made a few clarifications concerning control length and added a few pictures (Fig 9d...). The method described in the tutorial to determine the control length still applies, but if you use the ...SHO13 kit from K-Tech, the new figures shows the outcome and should save you the hassle of measuring, subtracting and so on. Just measure the cartridge rod as described, and make the control rod shorter by the specified amount. The dimensions given are valid provided you have also taken the needle tip off the stock adjuster clicker screw/rebound needle. I hope this will make this part of the operation a little easier. 

Kind regards,
Torbjörn.   

Hello,

Excellent write up; I must perform maintenance to my Marzocchi forks and would like to replace the fork legs or axle holder to one from a M695 that is black, my OEM are silver.

I saw that you mention to polish them, but, never saw how you took them out.

Thanks for any clarification on this subject.

Carlos

Hi, Carlos.
I´m not quite sure I get your question; the tutorial is only valid for Showa adjustable forks; I´ve never had reason to work on the Marzocchis and the non-adjustable Showas are pretty much beyond salvation other than regular service and fresh oil.

If there´s anything I can help you with, just let me know; as is I´m a bit unsure exactly what I can do.

Kind regards,
Torbjörn.     

This is the part I want to take off and replace with another one, but, not even on the Marzocchi manual says how to do it:

(http://farm9.staticflickr.com/8380/8652442523_1ab5ee2451_n.jpg) (http://www.flickr.com/photos/darkmonster620/8652442523/)
Fig1bBottomplugremoval (http://www.flickr.com/photos/darkmonster620/8652442523/#)

Hello Carlos.
I´m still not quite sure I ralize what you are intending, but if you want to change the fork bottoms of your Showa forks, this is what a set from a crashed 1000DS Monster looked like when I took them apart to see how it worked out: just use a screwdriver or something as a handle through the hole in the fork leg, and wind it out. These came apart real easy, maybe a bit of heating to break any loctite could ne required.    

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Showa%20Blues%20DMF/P4200118_zps5cd0ed16.jpg) (http://s855.photobucket.com/user/Monsterhpd/media/Showa%20Blues%20DMF/P4200118_zps5cd0ed16.jpg.html)  

There's a grub-screw to be removed first, yes?

So I thought too, but not on this one; not a trace of any grub screws, nor of a place it could have fallen out from. Not much trace of any of Loctite either, as a matter of fact, practically no torque necessary to unscrew the fork leg from the fork foot (fork foot ...? don´t know the proper expression for that part  ??? ).  

Anywy, maybe something to be added to the "Check list" when servicing the forks?  

I looked at two pair of Showa adjustable 43mm forks, they both had grub screws on the inside of the fork 'foot'.
About an inch above the 'showa' lettering.

They were '00 and '02 vintage forks.

Well,
it seems Showa found a way to save 0.002cents / fork set by leaving the grub screw out.
The lower leg is from a ST4S appr. 2002, and the loose foot from an S2R1000 Monster, appr. 2007.

I was surprised, and a little worried, at how easily the fork tube unscrewed from the fork foot.    

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/P4210118_zps4f54f78f.jpg) (http://s855.photobucket.com/user/Monsterhpd/media/Monster%20Forum/P4210118_zps4f54f78f.jpg.html)

Thanks, I will try

MonsterHPD, I wanted to let you know I attempted this with my Marzocchi 43mm lowers (from the conversion project on Ducati.MS .)

After removing the setscrew, the fork stanchion was completely immovable in the foot. I attempted heating in flame (stove had to do) until sizzling/smoking hot, then tried your method. It was wedged in solid. Looking through the setscrew hole, there was evidence of oxidization/rust. I suspect this is impedes removal of the foot.

My machine shop+sportbike shop says although they have a special jig for this, they do not attempt it routinely because of the difficulty. (labor = cheaper to get a new lower)
The specialist suspension shop says they do not use a vice, and instead have to use a hydraulic press to hold the stanchion in place. They then use a breaker bar on the foot. (labor + specialized tooling)

I suspect swapping feet is too difficult for the average person, and your Monster was an exception.

To Carlos: do not fret. The Marzocchi and Showa lowers seem interchangeable. If the lower tubes are of similar length, you can swap the bushings between the two and they will fit. Marzocchis utilize a thinner bushing than the Showas. Please see my post here:

(http://www.ducati.ms/forums/attachments/sport-classic/413594d1405066865-project-100-ohlins-bust-gsxr-cartridges-sc1000-stock-marzocchi-forks-748_marzocchi-sliders.jpg)
http://www.ducati.ms/forums/77-sport-classic/393201-project-100-ohlins-bust-gsxr-cartridges-sc1000-stock-marzocchi-forks-3.html#post3944474 (http://www.ducati.ms/forums/77-sport-classic/393201-project-100-ohlins-bust-gsxr-cartridges-sc1000-stock-marzocchi-forks-3.html#post3944474)

Ok, but, what I wanted to do was to swap the fork lowers from a Marzocchi used in a M695, that are black to my Marzocchi that are "regular" aluminium colour . . . ended up leaving as is for the exact same reasons impulsive_duc encountered

I believe that may no longer be accurate. I have found a 10mm compression adjuster screw that would allow Marzocchi users to use the GSXR conversion from the article you published. However, that specialized bolt would need to be purchased, and I am not sure of the cost.

You seem like you have the machining skill (and lathe) necessary to create such an item yourself. Would you be interested in attempting it? I can provide you an engineering schematic of the "theoretical" adjuster screw.

I will continue to investigate the commercial option.

You may be right, I´ve only ever tried that one fork. There was also no set screw on these forks.

If I remember correctly, all the 50mm/54 mm showas (i.e., Monster tc.) has the upper bushing with 1.0 mm wall thickness, and all the others (SBK´s) use the one with 1.5 mm wall thickness. Did confuse me once when pre-ordering parts.

You have a mail :)

Wow this is a great tutorial.  Thanks for documenting this as I would not have contemplated this otherwise. 

I'm thinking of trying this since I have access to a mill and lathe, and I scored some 900SS adjustables that need to be rebuilt, they don't rebound well and I think they may have the original fluid.   I have yet to order the K Tech parts.  I'm going to be putting this on my M620, which has the standard non-adjustable Marzocchis.  I'm new to playing around with the suspension.  I'd like to have all if not most of the tools needed ready when I attempt this. 

What is the size of the reamer that you used in 4f to clean out the burrs from the dimple drill out? Are there any other reamers needed?

I'm also thinking about using linear ohlins springs vs. race tech 0.85 rate springs, but have not decided just yet.  Any comments or advice regarding which springs to use?

Also what brand and viscosity oil did you use? 5W or 7.5W?

Hello,
I´m glad you find the tutorial instructive, or even inspirational :-)
Maybe it´s time for an update; I´ve done quite a few forks since this was written and I´ve gained some experience. There are quite a few alternative ways to upgrade the function of the basic 50/54 mm forks, some of which are:

•   Complete K-tech kit as per Showa Blues 1-2; this is best suited for track bikes since the ports are small, limiting flow.
•   Buy just the rebound piston holder / needle / spring / nut from K-tech, and use Racetech Gold valve compression pistons and shim set-up; this is better for the street, as are all the Showa stock pistons since both use big ports.
•   Transplant cartridge rod and compression pistons from some other Duc Showa fork (916/996/998/999); I think all Duc superbike forks after 888 have forks with proper damping circuit layout; 851 / 888 have the same rather useless setup as the 50/54 mm forks on Monsters etc. Or at least the few ones I´ve been into.
•   If you run clip-ons, the forks from 1000 SS are OK if you adapt the shim set-up (see Showa Blues Part 3). Or just use the relevant parts for your forks.
•   Transplant the cartridges from a Suzuki GSXR.

All these alternatives require various degrees of rework and fabrication and monetary input; none of them should be impossible with access to machine tools, some mechanical aptitude, time and patience.  
   
If I buy new springs, I use the 240 mm Öhlins springs, available in 0.5 N/mm steps frpm 7N/mm to 11 N/mm or so. To compensate for the shorter springs, I use 38 x 1.5 mm aluminium tubing in the bottom of the fork, plus the shim used for this purpose in most of the older Duc superbik forks.

The reamer is a 20 mm reamer, but since the holes needing de-burring are below the working area of the cartridge, I use a Dremel with a rather small wheel-type grinding tip and de-burr the holes, possible dress with some emery paper afterwards. The reamer is not really necessary unless you happen to have one handy.

I can put together a list of useful part numbers for those alternatives I´ve actually done myself, if you like.  

As for oils, I use 5W or 7 / 7.5W, mostly Motul; 5W for K-Tech (or Öhlins, almost identical), 7W for the others. I´ve not been systematic in my choice of oil brands which is not good; the 5W etc.  designations are not defined in any standard and actual viscosity can vary a lot for various xW oils from different brands.    

Thanks for the quick response.  I am new to all of the fork and suspension modification/rebuilding stuff. I had been reading on the other forum about modifications to the standard Marzocchi forks, I will leave those on the bike for now so that I can mess with the Showas, they are from a 900 SS and are 50/54mm.  I also need to wait for my clipons to arrive since the top of the forks protrude too far above the triple and end up interfering with the handle bar (I have a 2002 M620). 

I have access to some reamers but they are all fractional size, but that does not seem like a big deal to deburr, based on your comment.

I understand that there was a test in a UK magazine on the performance shocks that you had built. Sorry if I missed it but, can you advise where that I can possibly find a copy of that, I like reading about this stuff. 

Given there are so many combinations of modifications, what is the mod that you would suggest?  I will be doing this for a combination of street riding and track.  1)complete K-tech kit, 2)rebound piston holder / needle / spring / nut from K-tech, and use Racetech Gold valve compression pistons and shim set-up, 3) GSXR cartridge swap

Seems like if I get #1 and the Racetech Gold valves, I would have all the parts to do #2, correct?  I was initially going to just do the Gold valves until I stumbled on this thread explaining that there are still design issues with circuit design.

I don't mind spending some money on the parts, I just want to get the right stuff so I don't end up wasting money on stuff that I don't end up using. 

I can get a set of ohlins springs from a friend for $90, they are part number 8677-90 and I understand they were made for the 900SS.  He says the uncompressed spring length is 360mm.  I can't seem to find much other info on this spring, including the spring rate, would you happen to know?

The list of part numbers would be helpful. I'm sure I will have more questions as I start tearing into the forks.   
 

No problem with beeing new, this is no rocket science. It´s a good idea to do the Showas with no pressure to get them ready, always nice to be able to take things nice and easy.

I have the various Performance Bike articles as PDF´s; drop me a mail and I´ll mail them to you.   

What modification to recommend ... well, that depends. You need the rebound piston holders, and to my knowledge, K-Tech are the only people making them (apart from Showa, for all forks except the 50/54´s ...).
You could modify the stock holders and make your own needles etc; I have the drawings for that as well if you´d like to go that route, but it´s more bother than it´s worth. I only did them cause I found nothing else at the time.

I don´t think you´ll find the holders on K-techs on-line shop; you´d have to contact them. They have always been very friendly and helpful to me and expect nothing else if you contact them. The part numbers are as follows:

20K-MX006         FF REBOUND PISTON HOLDER SHOWA
20K-MX007A       FF REBOUND NEEDLE SHOWA
20K-REBSPRING   FF REBOUND NEEDLE SPRING
M6X1.00HN         FF PISTON ROD LOCK NUT M6x1.0

If you are mostly road and occasionally track, I´d say the big-port pistons (i.e., Showa stock, or Gold valves) are the better option. If nothing else, the big-port design leaves more room for shim set-up, and more room for comfort due to a higher flow capability.   

Gold valves or Showa stock is more or less a toss; hydraulically they are similiar and any differences are beyond the abilities of us mere mortals to detect.

I use the 240 mm Öhlins springs since they are an easy swap once you´ve done the initial installation. They will fit any 43 mm stanchion Showa (and probably any other 43 mm fork). Part numbers as follows:

4745-75, 7.5 N/mm (marking -75).
4745-80, 8.0 N/mm (marking -80).
4745-85, 8.5 N/mm (marking -85).
4745-90, 9.0 N/mm (marking -90).
4745-95, 9.5 N/mm (marking -95).
4745-10, 10.0 N/mm (marking -10)
4745-05, 10.5 N/mm (marking -05)
4745-11, 11.0 N/mm (marking -11)

As you can see, there´s a system to the designations, indicating the spring your friend has is a 9.0 N/mm spring. A stock SS spring is about 360 to 375 mm; I have some different notes and don´t know which one´s correct. I suppose a 9.0 N/mm spring could be OK for bare rider weights around 65 to 80 or so kilos; it´s a matter of much discussion and personal preference.

If there´s a need to compensate for shorter spring, the 996/998 (and maybe some others ...) have spring spacer tubes below the springs; and a spring seat washer ontop of the spacer; Ducati part numbers as follows:

Spacer: 349.1.099.1A
Washer / spring seat: 349.1.100.1A

I think the spacer is 75 mm long; there might be one 100 mm but I have no clear notes on this. If you need a longe tube, use alu tubing, 38 mm OD, and the washer on top of that. 

Finally, the GSXR (Showa) cartriges will fit with some work. They have 12 mm rods,as opposed to Ducati 10 mm, whis is considered an advantage since it provides more oil for the compression circuit to work with. They come in many different versions, and I don´t have much of a clue. The 2 sets I´ve bought are very different, but will both fit with some work. Might be a tutorial on that as well, one of these days  :-\

Well,I think that´s it. Any questions; just let me know and I´ll do my best to answer.     
   

I tore apart my forks, the fluid was in great condition and pretty clean, I suppose the previous owner had replaced it regularly. it actually seemed redish and seems alot like Automatic Transmission Fluid. 

You  mentioned to measure how much the rod stick out from the top of the lock nut to the tip of the shaft with the orfice. I was careful to not back down the locknot from the top cap when I did so.  I measured 15.40 mm. 

I also re assembled the fork without the spring.  I did put back in the spacer tube, I don't think that affects the measurement right?.  The purpose of this is only to measure the maximum total stroke, right?  I measured a total stroke of 112.0mm from full compression to full extension.  I did this for both sides and I got basically the same. 

I have not yet removed the bottom screw since I only had a 19mm 1/2" drive socket and it won't fit.  I will borrow a 19mm 3/8" from a friend later today so I can finish taking that apart and measure without the cartridge.

The measurement of the cartridge rod above the lock nut is just to help define the length of the rebound adjuster rod.

The 112 mm travel as you measured is probably with the hydraulic stops still in place (the white plastic things on the cartridge rod)? I always throw them out, so you should repeat this measurement after you´ve taken them (and the lock rings on the cartridge) out. Compare this measurement with the stroke of the final assembled cartridge rod; if the fork stroke is smaller than the cartridge stroke you´re safe. Without the hydraulic stops, fork stroke should be close to 120 mm; if you use the K-tech parts with internal thread o the rod / external thread on the holder on a 50/54 mm fork, it should not be a problem.  

One note here: On a fork I did some time ago, after final assembly the rebound needle would not move freely. After quite a bit of fiddling around, I swapped the cartrigde rods for a different pair and the problem disappeard. It turned out that the thread in the cartridge rods were not centered well enough, and this caused the needles to bind. I´ve heard of one more case like this, so if it should happen to you, you know the problem most likely was caused by Showa, not you or K-tech.            

Yes this was with the hydraulic stops in place, when I did it the bottom adjuster screw was still torqued to the cartridge, therefore it was not possible for me to remove the hydraulic stops at that point.  I was just following the steps.  I will pull the stops and remeasure today. 

I think I will go with racetech valves.  I will order those this week.

I have a trip to next week with a 1 day stop over in AMS, I was thinking that perhaps it's easier and quicker to get the K tech parts there. I live in California so shipping the parts internationally may cost a bit, although I figure it should be quite light in weight since these are small parts.  I will call up the K tech people in the UK on Monday and find out.

hi my friend , verry impressive job!!! I am the owner of an harley XL 1200S with a showa fork, looks like verry similar to yours
i wan't to lower (about 2 inches) this fork.. you think i can put a spacer in the cartridge? or other thing to do? can you help me?
i send you a private message.
if someone have an idea..
thanks a lot [bow_down]

Hello!

Excellent thread even today @MonsterHPD

I had an issue with my Marjokis that one of the outer tubes was cracked and checked my options to upgrade a little bit my M695

So, guess what.. I have a pair of the shows blues bought in bargain I would say from an ST4s (tined version) and I ordered the K-tech kit. Now I am through the process to make the modifications.

Well is quite difficult for me to find and aluminum rod but easy to find a stainless one which i ordered. Of course, is more robust but i don't know if the weight will affect it. Also i don't have a lathe to put the o-ring on this and with the covid now is difficult also to find a store open for that so may possibly will not touch it for now, or if i find a 3 mm bolt (i have a 4 one) i will make the thread on the top cover. What is your suggestion on that?  Also note the cartridge rod length on my forks was measured to be 39.1mm total length.

Furthermore, i would like to ask if the picture of the compression stack of k-tech (the lower one) should be installed as per picture or vice versa? The shims should be at the bottom or the top of the stack? As it came the kit the bolt was facing the head on the shims so I am confused since I try to understand how they are working as well. so pls clarify on that if possible.

Also, i understand that for the compression stack I have to use the bolt supplied by K-tech and not the one used with the original valve

Thanks for your time spending. I will take some photos of the tools made for the diburing and other holders as a less professional option

Hi,
glad you enjoyed the thread, glad if it can be of help.
See answers below.


Well is quite difficult for me to find and aluminum rod but easy to find a stainless one which i ordered. Of course, is more robust but i don't know if the weight will affect it. Also i don't have a lathe to put the o-ring on this and with the covid now is difficult also to find a store open for that so may possibly will not touch it for now, or if i find a 3 mm bolt (i have a 4 one) i will make the thread on the top cover. What is your suggestion on that?  Also note the cartridge rod length on my forks was measured to be 39.1mm total length.

I don´t think it will make a difference function-wise due to weight, and I put the O-ring there as much to keep things from faling apart during handling s anything else. I also don´t thin you need to bother with the set screws in the top nut, the forks will function well also without them. 391 mm (presumably) seems OK.  

Furthermore, i would like to ask if the picture of the compression stack of k-tech (the lower one) should be installed as per picture or vice versa? The shims should be at the bottom or the top of the stack? As it came the kit the bolt was facing the head on the shims so I am confused since I try to understand how they are working as well. so pls clarify on that if possible.

The shims on the base valve piston go on the bottom, they are letting oil out of the cartridge when the fork is compressing. The check valve goes on top, letting oil back in when the forks extend.

Also, i understand that for the compression stack I have to use the bolt supplied by K-tech and not the one used with the original valve

That´s right. The stock screw is too short for the K-tech kit (or any other proper piston-and-shim set-up)

Thanks for your time spending. I will take some photos of the tools made for the diburing and other holders as a less professional option

Please do so. It´s always interesting to see new solutions

Hi Again .

Your response is impressive and I have to mention it !

Thanks for the info

Now one more question:

In the SKF seal pack, it came with a plastic washer. When I removed the seals from the fork the same had already a metal washer.
The seal from SKf ,was with smaller width from the installed one.

Should I use the plastic washer from SKF only, the existing metal washer or both of them. I will try to measure now but when installed only the plastic washer and the seal the space available at the bottom of the fork was only for the lock ring (you could see I mean the lock ring groove) . So now I am confused if I installed correctly the seals and if the plastic washer I left inside is ok or I should put back the existing metal washer

By the way even by air is working find the cartridge ( I checked and all valves are installed properly  [cheeky] [cheeky])

Hello.

You should always use the metal washer; I install them with the flatter side towards the seal.The plastic washer is to compensate for the thinner SKF seal. Ioften find Thatcher with booth in place the snap ring won´t snap in, so I don`t use the plastic ring.

Use  a heat Gun to warm the slider area around the seal/Bush area, They Will go in/out much easier.

Hope tris comes out right, I hate the autocorrection on my nej IPad .....

Hi

Finally, I measured and installed the metal and the supplied plastic washer. They fit ok and snap ring installed also easily without problem

What I worry about is that I used medium adhesion locktite on the valves (just to keep you informed that I already installed the forks on the bike while I am in the process to overhaul an ohlins I bought,  while I replaced the fuel hose as well as proceed with several parts to be cleaned removed etc)

Of course not yet tested

Reverting

Hi,
I´m not quite sure what you mea with the Loctite comment. If it is of any heelp, I use a small dab of blue Loctite on the hollow screw for tha base valve, and a small dab of green (strong) Loctite on the rebound valve holder in the damper rod. Don´t use a big dab, I used too big a dab once and had to take it all apart since the needle got stuck.

Great thread!

I've just installed the cartridges from an early 2000s Aprilia Mille into the adjustable forks of a 1993 900SS and thought I'd share the info that might be helpful.  I got a lot of info from Pajazo and dspear99pa's posts on the MS Ducati forum (and this thread, of course!)

I'm restoring an old racebike and got started on this journey when I discovered a broken plastic "hydraulic stop" in one of the legs.  I started researching online (what is this thing?).  Naturally, it's not available as a part and Ducati only sells it as part of the cartridge assembly.  Fortunately, the consensus seems to be that it isn't all that important and can be removed.  

However, during all this research, I found threads, like this one, about the "faulty" compression circuit in some of these early adjustable forks.  I've worked on Yamaha YZF750 Kayaba and the Aprilia Showa superbike forks and those both have the tube that goes into the damping rod with the needle controlling flow in the cartridge.  The Kayaba tube is not attached to the fork cap; the Aprilia is.

So, I was contemplating finding a set of the GSXR forks when I remembered that I had a spare set of the Aprilia Showa Superbike forks.  I've always thought these were the same as the 748/916/996 variety, though I've never compared internals.  The only difference I'm pretty certain on is that the Aprilia rebound screw is not indexed (the manual states "2.5 turns of adjustment," whereas the Ducati, the 996 manual I checked, anyway, states a certain number of clicks.  They could likely still be 2.5 turns irrespective of indexing.

The Aprilia forks were pretty beat up, and someone had sawed off the fender mounts (why???), so they were pretty much good for parts.  Here's the info that might be useful (taken with a tape measure, so probably not exact):

1.  The cartridge diameters, rod diameters and rod threads are the same.
2.  The cartridge length on the Aprilia is approximately 2.0" longer than the Ducati unit.
3.  Compressed length of both cartridge assemblies is the same.
4.  Extended length of Aprilia cartridge/rod is .4375" longer than the Ducati.
5.  The fork cap on the Aprilia superbike fork is a larger diameter (as you would expect).
6.  Fork cap parts are interchangeable, so I swapped the blue-anodized inner-part of the cap (with the adjuster screw and rod) into the 900SS cap.

Here you can see the two fork caps and the cartridges.  It's obvious the one from the Aprilia is longer:

(https://live.staticflickr.com/65535/49850055563_15aedb4c82.jpg) (https://flic.kr/p/2iX5yLB)IMG_E3636 (https://flic.kr/p/2iX5yLB) by Michael Reed (https://www.flickr.com/photos/132042654@N06/), on Flickr

I assembled the fork caps onto the dampening rods (indexing them so they had the correct range of adjustment).  So, the Aprilia at 2.5 turns and the Ducati at 14 clicks (how I interpreted it from the old manual; it's not that clear if the text refers to the compression or rebound adjustment).  Then I measured the distance from the base of the cartridge (with seat washer) to where the fork cap lip rests on the top of the fork leg:

900ss compressed:  22-1/8"
Aprilia compressed:  22-1/4"
900ss extended:  26-9/16"
Aprilia extended:  27.0"
900ss bottom of inside of fork to top of fork cap threads (compressed):  21-11/16"

So, the fork range movement won't be hindered by the new cartridge.

I assembled the Aprilia cartridge assembly into the Ducati forks, using all of the other Ducati internals, along with the modified fork cap.

(https://live.staticflickr.com/65535/49850060678_fbdc322c25.jpg) (https://flic.kr/p/2iX5AhN)IMG_3639 (https://flic.kr/p/2iX5AhN) by Michael Reed (https://www.flickr.com/photos/132042654@N06/), on Flickr

One glaring difference between the two forks is the compression adjuster.  The banjo-style bolt that threads into the rod is the same, but the adjuster that threads into the casting on the bottom of the fork lower is different.  The Aprilia fork has a small orifice between the casting and the inside the fork and the adjuster is a needle to control flow.

The Ducati adjuster, well, I'm not really sure how that works.  The threaded casting is open to the inside of the fork and the adjuster is obviously a different mechanism to control flow.  Somehow, I didn't try to turn the adjuster with the assembly out to try and figure it out.  But, I'm doing the 2nd fork today, so will investigate further.

(https://live.staticflickr.com/65535/49850063848_7eb5656fc8.jpg) (https://flic.kr/p/2iX5Bes)IMG_3638 (https://flic.kr/p/2iX5Bes) by Michael Reed (https://www.flickr.com/photos/132042654@N06/), on Flickr

I'd be curious:  does anyone know how this adjuster works, and if there's any reason why this unit would not work with the "new" cartridge?

I assembled the fork and filled with Motul Expert 5W with an air gap of 130mm.  

I then tried the "bump" test with this fork compared to the other Ducati fork with the original internals.  Honestly, I couldn't tell much of a difference.  Worrying is that a couldn't tell a difference with either fork on compression with the comp adjustment backed all the way compared to turned all the way in.  Rebound damping seemed to work fine on both legs.

So, I'm wondering if everything is working as it should.  One thing I did notice during assembly.  When I assemble the YZF750 Kayaba fork, I always crank the compression adjustment in to slow the fall of the damping rod; it makes it so much easier to install the cap when compressing the spacer; I don't have to use wire or anything to hold the rod up because it falls so slowly.  I tried to do this with the 900ss forks with the Aprilia internals and noticed no change in the speed at which the rod fell no matter where the compression damping was set.  Normal for this fork?  I don't know.  It's been a long time since I did an Aprilia Showa fork, so I don't recall how those react.

I'm going to do the 2nd leg today, so will test the rate of fall on the Aprilia Showa fork when I disassemble.

One last thought:  The extended length of the modified 900ss fork is longer than the original; I didn't measure it, but it's probably the extra length of the Aprilia extended cartridge/rod assembly.  I can't imagine that would make too much of a difference. 

900 ss published travel:  120mm
Aprilia Mille pulished travel:  127mm

I was staring at some of the parts on the bench today when I noticed that the dimples that hold the compression in the bottom of the original 900SS cartridge had been drilled out.  So, I pulled out the cartridge and discovered it was a Racetech Gold Valve.  I have no idea what the valving is.

I did the bump tests some more on the forks and I now feel like I notice more compression damping on the 900ss fork with the Aprilia internals.  This is testing back-to-back with the rebound valve on both forks completely open, testing compression circuit either fully open or closed.

Not sure if this is better or not, but it's definitely different.

Hello,
Seems you have a good fork now. I have not checked your actual measurements, but it seems ok.
I have not checked the actual function of these adjusters, but they do seem to react less to "bouncing" than the other type.
The newer Duc Showas (848 etc) also have this kind of adjusters, and I noticed this characteristcs on them. K-Tech has a replacement adjuster that will react differently. If "better", I don`t know.
I have done some older 41 mm forks with this adjuster type recently, and they all feel a little like you describe. They still work properly in actual use, but may react slightly differently to adjuster settings.
The Gold valves are good, but be careful with the brass screws, they break easily ;  a little bit of old Loctite in the threads  was sufficient on one of mine ....
Racetech has a system with 0.15 mm shims, starting with smaller and adding 0.15x17 mm shims on top for stiffer action. I could dig out their guideline if you like.

Kind regards,
Torbjörn.

Thanks, Torbjörn. 

Nice to know about the compression damping mechanism.  I've found the Gold Valve instructions on Racetech's website, so I'm good.

I got pretty excited about having a set of forks laying around that I wouldn't use but could salvage the internals and everything dropped in to the 900SS forks with no modifications required.  I figured someone might benefit, if he doesn't want to do any fabrication, and prefer not to go through the process of adapting yokes, axles, bearings and spacers to use the superbike forks.  There are probably those who prefer to keep their bikes looking original.

Keep in mind that Race-Techs recommendations re shim stack is for the race track.

The conditions in the real world often differ.

Understood.  Bike is a period racer from the early 90's.  It won't ever see the street again, likely just the occasional AHRMA SE event and track days.  It's a cool bike, though...Pankle rods, twin plugged, Silent Hectik ignition, etc.  I'm going to see how the original forks feel with the Aprilia Showa internals sans Gold valve.  It probably doesn't matter too much, like all my bikes, it will be capable of going much faster than I am.

It sure is fun to tinker with though!

Great to know.

Sounds good, most of us don´t need a Panigale (would probably just scare me) to have fun and I also like the tinkering as much as the riding.
Anyway, assuming that the compression pistons are the ordinary Showa "big port" pistons, there´s no benefit by changing to the Gold valves, the difference (if any) in practice is not discernible (in my view, at least). You may need to change the shim set-up; in my view it´s easiest to start from the soft side. Too soft is usually quite easily noticed, too stiff has a way of feeling better than it is, and is tough on the tires.   

You will be able to see results of your adjustments, and to help you a tiewrap around the fork leg to keep track of fork dive will be a good help (assuming you don´t have a data-logger ....) 

Kind regards,
Torbjörn.

Hi guys, especialy Torbjörn  :) Im actualy tuning my supsension on S2R 1K. Im riding sporty on the street, on track too and my biggest problem is, that im now working as motojournalist per 3 years, so i know how should proper setup working   ;D I know, that my S2R will not be as bike with Öhlins EC or TTX gear unless i spend money for this stuff, which will be probably enough money for buy another bike  ;D Yes, i have little budget, so for the rear i go for S4R Showa shock. Im 65kg without gear, basic setup is 30mm sag and it looks better then standard shock. During winter i will be restore it and thinking about Race Tech Gold Valve for them. Is it worth for money or not?

And of corse, next question is the front. Soft springs are well known, so i ll go RT 0.85 to front and thinking again about different valving. I found RT rebound valve, Bitubo makes comp and rebound valving set and here i found your K-tech stuff. What will be the best choice for street/track use about 70/30%? Bitubo says, its racetrack only use, what about other stuff? Will not be too stiff on street? I preffer stiffer bikes but with good response when you feel quality of suspension and you feel that working well and that wheels nice copiing the ground... And for a bonus, in Czech republic we dont have a lot of nice tarmac, but im rather suffer little bit on worse road for nice support.

Can you recommend me solution please? Or is better looking for different gear? S4R or 916/996 forks for example? Thank you very much!

I will have to think about this one .... I´ll be back afterI do some research. 

Hi again.

One question ... do you have the adjustable Show fork on your bike? I have not worked on a S2R (i.e., 1000 cc motor?) so I´m not sure what fork are on them-

   

Hi, thank for research  [thumbsup] Yes S2R 1k have fully adjustable Showa, i cant say it properly but for first look it looks like same on M1000DS

Hello, I have some interesting news, but dont know if its possitive or not. On facebook one guy send me his experience with rebuild S4 Fork, which in his word would be same as at S2R 1000

"I have Racetech gold valves and springs. The valves were a pain in the ass to install because it required modification to the original damper. If I had to do it again, I’d probably consider a cartridge kit. To my knowledge, RaceTech only makes a compression valve for these forks. The valve makes for a more supple and less jarring ride on larger square bumps. The springs are shorter. I’m not sure why they do that but I followed this guys instructions and everything works fine for the last 7000 miles. The spring is also a linear spring rather than a progressive one like stock Ducati."

And here is link to his work: https://waste.org/~knobs/fork_rebuild1.html?fbclid=IwAR0EgeMNyNY48ZOWfuLcNgFWJPU6IAlN820HMEgxmYjJ48fay-S3uhXAX6Y (https://waste.org/~knobs/fork_rebuild1.html?fbclid=IwAR0EgeMNyNY48ZOWfuLcNgFWJPU6IAlN820HMEgxmYjJ48fay-S3uhXAX6Y)

Is the K-Tech set 20SSK-INT-SHO-13 more plug and play or not? If it will fit...

The link does not work on my computer, but for some reason on my phone .... so it looks like the first mod I made to my M900 forks, whih seem to be the same; as far as I know, all adjustable 50/54 mm forks except the SS1000DS are like this.

I don´t remember the gold Valve was any big hassle to install, and maybe there was a slight improvement as far as suppleness was concerned, at least on my 2nd attempt when I made the shim setup the softest in Racetechs shim setup table (I was about 59 kg at the time). I still have the Gold Valves on the shelf, with a broken brass screw which snapped when I tried to install it without first cleaning out the old Loctite. Don´t see the reason to use brass for this screw ...

What you do not get with this set-up is compression damping adjustability, it does almost no difference what you have the adjuster set to (I ran them fully closed, or one click out (there is a slight difference between those two settings).

I´d say the K-teck kit installation is decidedly more work since you have to manufacture the adjuster rod, organize / manufacture a hollow M6 screw for the compression piston / shim assy, and (preferrably) modify the top nut adjuster screw.
The piston in the K-tech kit is more track oriented (due to the smaller ports), but I have used them on road as well with no complaints, really.

So, in short form, the difference between the two solutions is the adjustability of the compression damping. 

As for springs, I use Öhlins springs, there are several springs from them that will fit with proper pre-load tubes.   

So... At first, thank you a lot for your experiences! At second, after all, i think, i will go through the 0.9 springs (K-tech or can you send your recommendation to proper Ohlins spring? Springs are the same for all Monsters, is it correct?) and only restore serial internals. It looks like a lot of work for mechanic, it will be a lot of money and finally springs+valves+work will be the sime like new cartridges from Adreani, wich i see like the best option for big improvement... SBK forks - new triclamps, restore, springs, 1000DS forks are like golden unicorn...

Last question, do you have some experince with Gold Valves at rear end?

Well,
I have an old list where quite a few part numbers are not more available, so supplied from old stock if there are any. I have used the 4745-xx springs, but they are going out of stock. So the list below are just some part numbers from the list, no guarantee. For reerence, a stock Monster spring is OD 38.6ish, wire diameter 5.1 mm.

Description                           
Part no/coulor                          Length     Inner dia.       Outer dia.   wire dia.      Rate   Stroke
Spring,Fr.fork   9 N/mm   04745-90   240             27.7       37.5           4.9              9           140
Spring,Fr.fork 38/287/9.0   08627-90   287     28               38                   5              9           165
Spring,Fr.fork 37.5/250/9.0   08692-90   250     27.7       37.5           4.9              9           143


I have no experience with Gold Valves for rer shocks.