ES Fork Cap Dissassembly

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#1
I am looking to soften the compression damping on my forks, it appears that the left fork has all the compression damping and the right fork all the rebound damping.
I recently took the left fork apart expecting to find the usual compression valve at the bottom of the cartridge but there was only a one way valve...it would let oil into the cartridge but not out. On compression, the oil is forced up the cartridge rod to the top of the fork to where the stepper motors are.

The options appear to be
A put thinner oil in the compression fork
B increase the air gap...to soften the spring
C replace the one way valve with a "normal" compression valve
D unscrew the stepper motors and change the valving there

Has anyone ever unscrewed the stepper motors from the fork caps ?

IMG_20190819_205936915[1].jpg
Any info greatly appreciated
 

holligl

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#2
I'm assuming you have tried the softest setting via the settings? I believe I read somewhere the specified oil is already pretty light (I think equivalent to 2.5w). Is yours original?

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#3
Yes, I've tried every setting available. I'm currently on the return leg of a trip to Romania and the roads over there really showed up the bikes limitations.
Had the bike from new, now at about 9k miles and am 84kg kitted up to ride.
 

fac191

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#4
Yes, I've tried every setting available. I'm currently on the return leg of a trip to Romania and the roads over there really showed up the bikes limitations.
Had the bike from new, now at about 9k miles and am 84kg kitted up to ride.
The preload settings make a difference to the damping. If your not carrying much gear you could ride on the one helmet setting.
 
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#5
Yes I have the damping sheet as posted on the forum and have tried all the range of settings.
While riding today it occurred to me that heavier guys than me find a stiffer rear spring works for them. Conversely, it seems logical that lighter riders may find a softer front would work for them , perhaps softer fork springs ?
 

holligl

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#6
The options appear to be...
B increase the air gap...to soften the spring
I don't understand this one...
Yamaha is very specific on the oil level. I wouldn't play with that. Not sure what your warranty situation is, but you would likely be voiding any remaining warranty with most of these.

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#7
I don't understand this one...
Yamaha is very specific on the oil level. I wouldn't play with that. Not sure what your warranty situation is, but you would likely be voiding any remaining warranty with most of these.

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It is widely know that the air gap can be increased to give a plusher ride and vice versa. The air gap has a spring effect as it is compressed.
Re the warranty, you are probably correct but it will run out over the winter anyway, I'm just trying to gather info at the moment.
 

holligl

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#8
What are folks using to remove the ES fork cap? Looks like a 43mm but it seems hard to find that size in a socket. Will a large adjustable wrench do the job without messing up the cap?

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Nikolajsen

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#9
NO NO:eek::).
I have read here, that there is some kind of plastic tool for this..
I would use a socket with some papir or simmilar to protect..but then, I already have the socket:cool:
 

Bart

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#10
There is a tool, but I read on here that a good quality open ended wrench will do the job with some wrapping around the nut. I tried this and it does work, the fork cap nuts came off no problem.

However, it would appear that there is no answer to my question in the opening post

"Has anyone ever unscrewed the stepper motors from the fork caps ? "

I was hoping the collective wisdom of the forum could supply and answer......
 

holligl

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#11
There is a tool, but I read on here that a good quality open ended wrench will do the job with some wrapping around the nut. I tried this and it does work, the fork cap nuts came off no problem.

However, it would appear that there is no answer to my question in the opening post

"Has anyone ever unscrewed the stepper motors from the fork caps ? "

I was hoping the collective wisdom of the forum could supply and answer......
Answer to your specific question may be no...

I did find some 43 and 44mm sockets on Ebay and Amazon. In rechecking, the best measurement I can get is 43.7mm. Is a 44mm the best?

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holligl

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#12
NO NO:eek::).
I have read here, that there is some kind of plastic tool for this..
I would use a socket with some papir or simmilar to protect..but then, I already have the socket:cool:
Thanks, can you tell me the size?

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ocgeek

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#15
I am looking to soften the compression damping on my forks, it appears that the left fork has all the compression damping and the right fork all the rebound damping.
I recently took the left fork apart expecting to find the usual compression valve at the bottom of the cartridge but there was only a one way valve...it would let oil into the cartridge but not out. On compression, the oil is forced up the cartridge rod to the top of the fork to where the stepper motors are.

The options appear to be
A put thinner oil in the compression fork
B increase the air gap...to soften the spring
C replace the one way valve with a "normal" compression valve
D unscrew the stepper motors and change the valving there

Has anyone ever unscrewed the stepper motors from the fork caps ?

View attachment 59155
Any info greatly appreciated
Are you saying that you opened the cartridge and the above picture is all that is inside of it ??
 

Bart

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#16
Are you saying that you opened the cartridge and the above picture is all that is inside of it ??
The picture shows what is normally the compression valve at the bottom of the cartridge.....but it is a one way valve. I have not yet removed the damper rod piston (don't have the correct tool for that)
 

ocgeek

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#17
Ah ok as i thought. That is the flow through valve (and there is an analogous one in the other fork)
What makes the hydraulic work is inside the cartridge indeed.
That is the peace you (or better a specialist) would work at (e.g. revalving) to make amendments to the perceived behavior of the suspension.
I've seen 3rd party kits (e.g. the Holins) which have broader ports at the bottom (the piece you have pictured with the tiny holes) but on the other hand has larger cartridges and tougher hydraulics (e.g. move more oil and restrict it)
The valve itself (and the hole in the cartridge) is only controlling the mass of oil (and its speed) which can be sent to the hydraulic to work with. On top of that viscosity (speed of the fluid and thus again mass) can alter things too.
In the end all things need to be balanced well - normally by someone who knows the behaviors by having been in this field for ages... suspensions are not an easy beast to master
 

Bart

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#18
Ah ok as i thought. That is the flow through valve (and there is an analogous one in the other fork)
What makes the hydraulic work is inside the cartridge indeed.
That is the peace you (or better a specialist) would work at (e.g. revalving) to make amendments to the perceived behavior of the suspension.
I've seen 3rd party kits (e.g. the Holins) which have broader ports at the bottom (the piece you have pictured with the tiny holes) but on the other hand has larger cartridges and tougher hydraulics (e.g. move more oil and restrict it)
The valve itself (and the hole in the cartridge) is only controlling the mass of oil (and its speed) which can be sent to the hydraulic to work with. On top of that viscosity (speed of the fluid and thus again mass) can alter things too.
In the end all things need to be balanced well - normally by someone who knows the behaviors by having been in this field for ages... suspensions are not an easy beast to master
ocgeek,
I think you have misunderstood my opening post. The valve in the picture, unlike a normal compression valve, only passes oil one way. It will let oil into the bottom of the cartridge but not out and does not control the compression damping. On a compression stroke oil is forced up the centre of the hollow cartridge damper rod to the top of the fork where the stepper motors are and I assume where a compression shim stack is. Hence my question "has anyone unscrewed the stepper motors from the fork cap".

As a bit of background, I admit I am no expert but I've re valved many motorcycles over the years, modified existing valve ports etc, yes it is a tricky subject and one never stops learning.
 

ocgeek

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#19
Understood but i think (admit have not seen it first hand) the cartridge is not hollow. It shall host the shim stack (sorry i keep calling that valving) which in the end influence the hydraulic behavior.
I cant's think the good Yamaha's just put a one way valve, a hollow tube (cartridge) and a tiny hole on top of the cartridge to cope with the dumping. That can't be. My Honda bike is done like that but it has a much much simpler fork tube (aka flute style)
The cap IMHO hasn't any valving shim stack inside. The step motor just pushes (+/-) a tiny rod which pushes something which is in the cartridge which is the actual shim stack valving control.
In the previous model (MY2011) the valving was controlled at the foot of (both) the fork(s)...and at the top cap.
The MY2014 and beyond have asymmetric regulations; compression and extension are sitting separately in L/R fork respectively and the control is only from the top cap which pushes a tiny rod vanishing into the cartridge
IMHO opening the cartridge you shall find what you are looking for
Apology if messed up the thread :p
 

Bart

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#20
No apology needed at all.
These ES forks appear to be different from a "normal" cartridge, there was no "tiny rod" as is usual.
 
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