which fork tube is which

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Yeah i do agree with you about the naming for the parts, i always called them cartridges as they look like the innards of a shock. But i've seen them called many different names and i am honestly unsure which is the proper one.
 

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But i've seen them called many different names and i am honestly unsure which is the proper one.
It happens all the time that somebody regularly uses a name or abbreviated name or abbreviation for some part that is not the name on a Honda or other bike fisch. I try not to be concerned unless the name used actually belongs to another part and would/does confuse me.
 
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Mu understanding is the right side (non ABS) is the damper side and the left is the cartridge side.
I can assure you that my non-ABS1990 model has the cartridge on the right side, the damper rod is on the left antidive leg.

My understanding is that the cartridge terminology refers to the fact that all damping force is generated within the cartridge. On a damper rod fork, the damping force is created by the movement of the rod through the end of the fork leg.
 
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There is a spring inside the right non-ABS ST1100 fork damper (aka. “cartridge�)? I'd be interested in seeing the guts of one...

John
Ask, and ye shall receive. The damper shaft assembly at the top is from my VFR800, the bottom one is the from the right leg of the ST. That spring contacts the inside top of the cartridge tube and stops further extension.
If you've not disassembled a cartridge, they are a lot like an old-style bicycle pump, with a moving piston (as in the pics) connected to a shaft which is attached to the fork cap. In the piston is a one-way check valve that opens to allow free flow in one direction (compression) and closes in the other, forcing oil to pass through restrictions caused by shim, so the valve creates damping force on rebound only. There is a matching valve fixed at the other end of the cartridge tube, that has a check valve that opens on extension and closes on compression forcing oil through shim stacks. The compression flow is 1/3 that of rebound as the oil is displaced only by the shaft, whereas for rebound the volume swept by the piston has to pass through the shims.

IMG_2419.jpg
 

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.... The damper shaft assembly at the top is from my VFR800, the bottom one is the from the right leg of the ST. That spring contacts the inside top of the cartridge tube and stops further extension....
Thanks! Looks like a stiff spring. Probably why I didn’t notice when I’ve pulled the rod up... should have known though. How does one disassemble the damper?

So... as I understand it, some folks are buying the right folk cap that has a threaded hole on the bottom and obtaining a damper rod assembly (not available new stock from Honda) and installing them in the left fork... correct?

John
 
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So... as I understand it, some folks are buying the right folk cap that has a threaded hole on the bottom and obtaining a damper rod assembly (not available new stock from Honda) and installing them in the left fork... correct?

John
that's how I interpret it, but I think you also have to modify it so you have equal compression/rebound damping capability, as the stock setup was biased towards rebound only. I think that's what the Gold valve modifications achieve, but I'm just guessing. What isn't clear to me yet is why this would be preferred over using the left fork as is, and putting a Gold valve cartridge emulator in the left fork, which seems like less work. Maybe its easier to tune the cartridge style Gold valves, so having two cartridge forks makes that process easier and/or more versatile?
 
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Well for me i've rode a lot of older bikes and they all have the damper type forks, it's a older system that quite frankly doesn't work as well. Pretty much all the new bikes have the cartridge style and all the ones i've ridden dampen really well, there's a reason racetech sells gold valve cartridge emulators. As i stated in a previous post my cb1000 had cartridge style forks and it rode really well for a 600lb bike, and i figured i would give it a try on this bike see if i liked it. Oh and i forgot to mention John, i had a set of forks that were junk but had good innards that's how i got the parts to do this
 

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So... what you’re calling a “cartridge” is the fork “piston” in non-ABS ST1100 left forks. And you are removing the “damper” rod unit and cap from your right fork and are replacing it with a salvage “cartridge”/“piston” and cap from a left fork. Correct?

IOW, I had it backwards in my post above (#25).

John
 
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Likely just being dense, but after multiple readings of this thread and others that I have saved in the past, I'm still confused about this topic.
Cartridge vs damper. As an example, in TerryS's post above, it seems the terms damper shaft and cartridge tube are both used in reference to the right fork. So which is it? :)
I would really like to finally understand the language of our 1100 forks.
I think this may be the first time I've used something that is apparently called a 'smiley'.
 
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Sorry if I confused everyone.Pic 1.jpg

The attached picture is of some disassembled ST1100 forks (not my picture as I always have a good coating of fork oil all over me by this stage), 'helpfully' reversed side for side so the left antidive fork is on the right, and the right fork leg is on the left.

You can see the cartridge damper on the left, the skinny tube with a shaft leading up and out to the fork cap. Inside the tube is the moving rebound piston (on the end of the shaft) and at the bottom of the tube is the stationary compression piston. In this photo the bright silver piece on the lower end of the cartridge is the oil lock piece, which adds a hydraulic bumpstop as the fork tube end passes that point. Damping force is generated by flow through fix bleed orifices, and then by shim stacks being pushed off their seats at higher flow, which gives a linear response to suspension speed, allowing a controlled ride at low speeds, but the ability to smoothly soak up the faster hits without transferring too much jolting to the chassis. Cartridges are infinitely tunable with variables such as oil port size, bleed port size, shim configuration, and these can be different for rebound and compression because there is a separate valve for each function.

On the right is the damper rod fork, where the top end of the damper rod acts as a piston within the fork tube, compression damping is controlled by flow through the larger orifice and rebound damping is controlled by a smaller port and check valve at the lower extremity of the rod. All damping force is generated by oil flowing through the orifices in the rod, and this can be a compromise in that damping force increases with the square of the oil velocity. That means little or no damping (control) at low suspension speed, or too much at high speeds (approaching hydraulic lock), and a tough job finding the sweet spot. Cartridge emulators disable the compression damping function (by adding more holes to allow free flow) of the damper rod, and add a cartridge-like check valve and sprung shim to handle compression damping duties. The emulator just slips into the top of the rod and and is held in place by the main suspension spring.

On my bike I now have two cartridges, with one purchased off eBay replacing the damper rod in the left leg. I also have aftermarket valve bodies (Daugherty Motorsports) with custom shim stacks and stiffer straight-rate springs. If anyone wants my build recipe I am happy to share.

Disassembling the cartridges is pretty easy, just push the compression valve holder inwards to expose a small circlip, remove that and then the compression valve assembly will slide back out with just an o-ring seal for resistance. The rebound valve will slide right out of that end as well on the end of the damper shaft. The valves are simply held together by a socket head bolt (compression) and a 10mm nut on rebound, although the ends of the thread on the rebound valve are peened over and must be ground off to free the nut. And that's it, the shims will now slip off the valve assembly, but their sequence is important so don't mix the different thickness and diameters up.

The ST fork in my 1990 model was definitely biased towards comfort not control. The spring rates are not high, the compression damping is very light with a lot of free bleed and thin shims, and the rebound is similar but not as soft. This means it stays fairly soft and supple, but will also pogo and wallow when pushed harder. If you do most of your riding on smooth mostly straight roads, that is a good set up, but I don't live anywhere like that.
 

ST Gui

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Over the years I've read several references to cartridges used for fork tube suspension. I knew it was different than the suspension in my much older bikes.

Is the cartridge mentioned in this thread the same type of cartridge that I've read about in the mags or is this something new/different/separate?
 
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Well hopefully i can remember all the questions to answer. Ok, John that's the reverse of what i'm doing i have 2 cartridge (the part that looks like a shock) units and the rest of the fork parts are what's normally there. Here's a pic i'm using 2 of the top parts IMG_6732_zps71e24551.jpg , which i call cartridges. The cartridge style forks can allow for better damping as they are immune to fork rock and most internal wear issues that can cause improper damping of the forks and depending on design can allow for easy adjustment of bound and rebound as well as spring pressure.
 
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So based on the assumption that the stock cartridge unit (on top) was only designed to provide rebound damping, if you put two stock units in you'll have two rebound dampers and no compression dampers. I'm also assuming that's obvious, so what modifications are you doing related to the gold valve reference you made much earlier in the thread to provide the compression dampening?

BTW, as you're probably aware, there are no external adjustments on either of the stock forks, so your comment about easier adjustments is a bit confusing. On most other cartridge forks there are compression/rebound damping adjustment screws, and spring preload screws, but those are an integral part of the design and don't seem like something that could be added on later with a simple mod. Maybe you were just making a general comment about cartridge forks in general, and didn't mean to imply that was the case with the ST1100 forks.
 
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John OoSTerhuis

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So.... I had it right in post 25 and wrong in post 28. Arrrrgh.........

OK... so now, if you’re putting the guts of the right fork (the damper rod {“cartridge”}) and cap into the left side, AND... the right and left fork tubes are of different lengths and have different part numbers, shouldn’t the left side fork tube be replaced with a right side version tube also?

Another question: are the bottoms/ends of the two fork tubes also different... size of opening, e.g.? I don’t remember when I had mine apart. TIA

And can we quit calling the darn Fork Piston in the left fork a damper rod...? Please?

John
 
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Over the years I've read several references to cartridges used for fork tube suspension. I knew it was different than the suspension in my much older bikes.

Is the cartridge mentioned in this thread the same type of cartridge that I've read about in the mags or is this something new/different/separate?
Yes the cartridge in the ST is of the same general design as most other cartridge dampers, I know for certain many parts are interchangeable with the Showa forks in VFR800's, VTR1000F and CBR600 and 900, and also my old Suzuki RF900.

As I referred to earlier, the design is infinitely tunable for different duties, so it is a straightforward manner for those skilled in the art to alter the characteristics to suit a track bike, off-road bike or tourer. This is done by changing the bleed port size and the shim stack configuration (number and thickness of shims, as they behave like a leaf-spring in an older car). Fancier versions will have some external adjustments for the bleed port in the rebound valve (e..g. my VTR1000F has that, the flat-head screws in the forkcap are the tops of long needle valves that seat in the rebound valve body) or the bleed port in the compression valve (e.g. CBR600F4 forks have a small external needle valve near the bottom of the fork leg).

IMHO cartridge dampers are much superior to damper-rod designs as they are easily altered and have much more progressive response to differing suspension loads with less compromise than damper rods.
 
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So based on the assumption that the stock cartridge unit (on top) was only designed to provide rebound damping, if you put two stock units in you'll have two rebound dampers and no compression dampers. I'm also assuming that's obvious, so what modifications are you doing related to the gold valve reference you made much earlier in the thread to provide the compression dampening?
Nope, the cartridge design always has a moving rebound valve on the end of the damper shaft connected to the fork cap, and a compression valve fixed in the bottom of the cartridge.

Gold valves replace the stock valve bodies, and they differ by having much smaller free bleeds than stock, larger oil ports and a custom shim stack. Actually a lot of what you are buying is RaceTech's know-how when it comes to setting up the custom shim stacks to suit different bike weights and rider expectations.
 
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So.... I had it right in post 25 and wrong in post 28. Arrrrgh.........

OK... so now, if you're putting the guts of the right fork (the damper rod {“cartridgeâ€}) and cap into the left side, AND... the right and left fork tubes are of different lengths and have different part numbers, shouldn't the left side fork tube be replaced with a right side version tube also?

Another question: are the bottoms/ends of the two fork tubes also different... size of opening, e.g.? I don't remember when I had mine apart. TIA

And can we quit calling the darn Fork Piston in the left fork a damper rod...? Please?

John
Sorry John, but I and the rest of the motorcycling world are going to stick with damper rod and cartridge. :)

http://racetech.com/articles/CartridgeForks.htm

You pose some good questions in the rest of the post.

The fork tubes perform a couple of key duties. One is sliding through the bushings and keeping the fork straight, the other is engaging with either the damper rod piston and the top-out spring on the left leg to limit extension and bottoming, or entering the oil-lock piece on the right leg and limiting bottoming that way.

By replacing the damper rod with a cartridge with internal top-out spring, the left fork tube should only need to be the right size to engage the oil lock piece and resist bottoming. I think because of the antidive mechanism, there is not enough clearance for the oil lock piece to fit in the left leg but the cartridge fits just fine. So potentially my modified fork has a little less bottoming resistance as I have the oil lock in the right leg only. Bear in mind this is the bottoming stop we're talking about, and stiffer springs and decent compression damping make this mostly redundant anyway. Beyond that, the length of the tube is unimportant, and I have been riding for 20,000km now with zero problems.
 
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Nope, the cartridge design always has a moving rebound valve on the end of the damper shaft connected to the fork cap, and a compression valve fixed in the bottom of the cartridge.
OK, thanks for the clarification. so if that's the case, why did Honda use two different styles of fork legs if the right leg (non-ABS) performed both compression and rebound damping functions???
 
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OK, thanks for the clarification. so if that's the case, why did Honda use two different styles of fork legs if the right leg (non-ABS) performed both compression and rebound damping functions???
Hmmmm... cost and marketing would be my guess.

They invested a fair amount in the development and promotion of the TRAC system, and my guess is they were reluctant to toss it away, and it would only work with a damper rod design. However from the early 90's, the better performing Honda's had moved to cartridge forks. Cartridges are no doubt more expensive to make and install. Damper rod forks live on in most low-priced smaller bikes (e.g. CBR500's).

Interesting to note the latest Showa forks using the "Dual Bending Valve" are a sort of cartridge/damper rod hybrid offering the simple installation of the latter with some of the damping characteristics of the former. These have shown up in some recent HD's, the CB1100 and CBR650 IIRC.

https://www.showa1.com/en/technology/motorcycle/sdbv.html
 
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