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Discussion Starter · #1 ·
Hi all.

Perhaps this may help those experiencing clutch slipping after installing the hydro clutch kit combined to the 2nd generation clutch kit.

On my 2007 '9 with 63K miles (approx. 100K Km) and hydro clutch I have to put new clutch disks in, because I continued to experience clutch slipping under heavy engine load in 3rd and 4th gears after mounting a complete 2019 clutch kit, 8K miles ago (2019 kit comes with longer/softer springs and one disk more than 2007). Riding gently I don't notice any slipping, unlike under heavy load where the engine RPM rise fast but the bike is slow to accelerate. With the stock clutch (2007) I did not have this problem at all, while I noticed this problem as soon as the 2019 kit was mounted. I also tried to compensate for the slipping by screwing more in the nut at the slave cylinder to have its arm going higher - this helped for a 500 Km, but after the slipping came back.
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Indeed last week my mechanic (Suzuki this time) tested the bike after I explained him the slipping problem and told me that he could not say that this was a true slipping problem, although he confirmed that the clutch behaved in a strange way. In 1st gear, for example, by releasing the clutch lever quickly he could make a slight wheeling under strong acceleration and apparently there was no slipping also in 3rd and 4th gears, but by releasing the lever more gently he noticed what I described to him. It was like closing a door by pushing it gently and it does not close well or by slamming it and it closes perfectly.
So we agreed to open the clutch for inspection and this morning he showed me that different disks are burnt, with plenty of cork powder inside the clutch basket !!

The mechanic also measured the springs' compression with a dedicated tool and determined that a 2019 spring requires 25 Kg to compress it 2.5 cm from total extended, against 30 Kg for a 2007 spring (indeed it was already known that the newer springs are softer). For 6 springs, it makes a 30 Kg difference.
They also compared the pull effort at the clutch lever and measured 14-15 Kg with the 2019 springs, against 16 Kg with the 2007 springs. In addition to this the mechanic thinks that the hydro clutch is less efficient than the stock cable to allow the clutch to properly compress and avoid slipping.

So we think that the combination of hydro clutch + 2007 clutch kit (or any 1st generation clutch kit) works fine, but hydro + 2019 kit. So we've decided to install a 2007 clutch kit to remove the slipping (although the pull at the lever will be higher).

I'll report back on the end result.
 

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That's interesting Dommy, thanks for sharing. So basically the hydraulic clutch doesn't release the clutch fast enough to get enough initial grip, so then it slips. I never thought it would work that way, but yours is proof. I guess maybe a softer release leaves more oil between the plates, thus making it more likely to slip.
 

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So basically it looks like the oil from slave cylinder
is returning too slow back to primary cylinder.
Before I would change any expensive parts, I would
try to thorroughly clean the hydraulic system.
JMHO. Cheers 🍻
 

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Discussion Starter · #5 ·
Hi folks.

An update on this.
Yesterday the Suzuki mechanics returned the bike to me and now it runs well, no clutch slipping anymore (y) .

They installed all the discs from a new 2007 clutch kit and now no matter how hard you accelerate in what gear - you feel the clutch grab strong and all power is transferred to the rear wheel.
The clutch lever pull is a little harder than before with the 2019 clutch springs, but it's not a problem to me (maybe it could bring some excessive fatigue to the hand on long and aggressive rides on mountains, I will see next year with the spring).

What is definitely different is how quick the clutch engages - when the clutch lever is depressed a little, the bike starts to move.

Another glitch that the mechanics discovered is that my hydro clutch (installed in 2013) is not consistent with the pull, in that if the lever is often pressed/depressed (like in traffic conditions) the pull is constant, when instead the lever is not depressed for a while the clutch disengages late (the first 50% of the lever movement span is soft), although the slave cylinder still manages to disengage the clutch discs. Actually I was aware of the glitch, but it never bothered me.
They suspect that this is somehow due to vibrations affecting the slave cylinder's alignment and one remedy could be to disassemble the slave cylinder and install inside a small spring (with 3 or 4 kg strength) to assist the cylinder's piston at reaching full extension.
Questions for all: do you know is the slave cylinder is serviceable? Can you open it?

Furthermore, they aligned the two throttle bodies because one cylinder worked much less than the other and reset the idle regime at 900 RPM at cold engine (but it goes up to approx. 1100 RPM with warm engine). The end results is that at idle the bike is much less noisy, vibrates less and the acceleration is smooth and powerful :).

My M109R is the first bike that this dealer saw in his life (here in Italy this bike is as uncommon as a white mosquito), but they know to work (they prepare also racing bikes).
 

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Hi folks.

An update on this.
Yesterday the Suzuki mechanics returned the bike to me and now it runs well, no clutch slipping anymore (y) .

They installed all the discs from a new 2007 clutch kit and now no matter how hard you accelerate in what gear - you feel the clutch grab strong and all power is transferred to the rear wheel.
The clutch lever pull is a little harder than before with the 2019 clutch springs, but it's not a problem to me (maybe it could bring some excessive fatigue to the hand on long and aggressive rides on mountains, I will see next year with the spring).

What is definitely different is how quick the clutch engages - when the clutch lever is depressed a little, the bike starts to move.

Another glitch that the mechanics discovered is that my hydro clutch (installed in 2013) is not consistent with the pull, in that if the lever is often pressed/depressed (like in traffic conditions) the pull is constant, when instead the lever is not depressed for a while the clutch disengages late (the first 50% of the lever movement span is soft), although the slave cylinder still manages to disengage the clutch discs. Actually I was aware of the glitch, but it never bothered me.
They suspect that this is somehow due to vibrations affecting the slave cylinder's alignment and one remedy could be to disassemble the slave cylinder and install inside a small spring (with 3 or 4 kg strength) to assist the cylinder's piston at reaching full extension.
Questions for all: do you know is the slave cylinder is serviceable? Can you open it?

Furthermore, they aligned the two throttle bodies because one cylinder worked much less than the other and reset the idle regime at 900 RPM at cold engine (but it goes up to approx. 1100 RPM with warm engine). The end results is that at idle the bike is much less noisy, vibrates less and the acceleration is smooth and powerful :).

My M109R is the first bike that this dealer saw in his life (here in Italy this bike is as uncommon as a white mosquito), but they know to work (they prepare also racing bikes).
... is the slave cylinder is serviceable? Can you open it? ...
When I was looking into hydroclutch, Rainey was using Frando
slave cylinders, he even changed the model at least once, so
I would contact Frando, and talk to them...
PS:
have you considered external support spring to assist the
cylinder's piston at reaching full extension? Even the good
system flush might help if the fluid seems to be moving slow...
 

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The way you describe the clutch action, it kind of sounds like either the master or slave is not holding pressure. When/if you get in there, see if the o-rings are replaceable. It's like when the brake master cylinder on a auto is going bad, they start leaking fluid around the cylinder and the brakes won't stay as firmly engaged. Same for the slave cylinder or brake caliper on a car.

And did they happen to say why the 2007 clutch worked but the 2019 didn't? Odd that if the newer one was installed with all the correct parts that it would work less well than the older one.
 

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... is the slave cylinder is serviceable? Can you open it? ...
When I was looking into hydroclutch, Rainey was using Frando
slave cylinders, he even changed the model at least once, so
I would contact Frando, and talk to them...
PS:
have you considered external support spring to assist the
cylinder's piston at reaching full extension? Even the good
system flush might help if the fluid seems to be moving slow...
Ferodo ?
 

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Discussion Starter · #10 ·
The way you describe the clutch action, it kind of sounds like either the master or slave is not holding pressure. When/if you get in there, see if the o-rings are replaceable. It's like when the brake master cylinder on a auto is going bad, they start leaking fluid around the cylinder and the brakes won't stay as firmly engaged. Same for the slave cylinder or brake caliper on a car.

And did they happen to say why the 2007 clutch worked but the 2019 didn't? Odd that if the newer one was installed with all the correct parts that it would work less well than the older one.
Yes, it would be a good idea to check the cylinders O-rings as it should be done regularly with brakes master cylinders (usually cylinder maintenance kits are available from motorcycle suppliers). Nevertheless I did not see any oil leak from either the cylinders.

The Suzuki mechanics determined that the 2nd generation of clutch kit comes with longer, but softer springs than the 1st generation kit and it may be possible that using the hydro clutch the softer springs are unable to maintain compressed the clutch discs, hence the slipping. We have to remember that the hydro clutch's master cylinder is by Suzuki, yes, but not exactly designed for our bikes - it's an adaptation only, although a good one.

More, I checked my log booklet where I record all the story of my '9 (dates, mileage, items serviced, etc.) and I saw that when I had the hydro clutch installed in 2013 (I had still the stock clutch) I felt a minor slipping in 2nd gear under strong acceleration. After a while this glitch did not bother me anymore.

But with the softer springs of the 2nd generation clutch kit, it is possible that the best set-up would be based on the stock clutch cable.
It would be interesting to get feedback from those with the 2nd generation clutch with hydro clutch?
 

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Yes, it would be a good idea to check the cylinders O-rings as it should be done regularly with brakes master cylinders (usually cylinder maintenance kits are available from motorcycle suppliers). Nevertheless I did not see any oil leak from either the cylinders.

The Suzuki mechanics determined that the 2nd generation of clutch kit comes with longer, but softer springs than the 1st generation kit and it may be possible that using the hydro clutch the softer springs are unable to maintain compressed the clutch discs, hence the slipping. We have to remember that the hydro clutch's master cylinder is by Suzuki, yes, but not exactly designed for our bikes - it's an adaptation only, although a good one.

More, I checked my log booklet where I record all the story of my '9 (dates, mileage, items serviced, etc.) and I saw that when I had the hydro clutch installed in 2013 (I had still the stock clutch) I felt a minor slipping in 2nd gear under strong acceleration. After a while this glitch did not bother me anymore.

But with the softer springs of the 2nd generation clutch kit, it is possible that the best set-up would be based on the stock clutch cable.
It would be interesting to get feedback from those with the 2nd generation clutch with hydro clutch?
Throwing parts at it without finding the cause is absolutely ridiculous. You need a better mechanic , not more parts.
 

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Yes, it would be a good idea to check the cylinders O-rings as it should be done regularly with brakes master cylinders (usually cylinder maintenance kits are available from motorcycle suppliers). Nevertheless I did not see any oil leak from either the cylinders.

The Suzuki mechanics determined that the 2nd generation of clutch kit comes with longer, but softer springs than the 1st generation kit and it may be possible that using the hydro clutch the softer springs are unable to maintain compressed the clutch discs, hence the slipping. We have to remember that the hydro clutch's master cylinder is by Suzuki, yes, but not exactly designed for our bikes - it's an adaptation only, although a good one.

More, I checked my log booklet where I record all the story of my '9 (dates, mileage, items serviced, etc.) and I saw that when I had the hydro clutch installed in 2013 (I had still the stock clutch) I felt a minor slipping in 2nd gear under strong acceleration. After a while this glitch did not bother me anymore.

But with the softer springs of the 2nd generation clutch kit, it is possible that the best set-up would be based on the stock clutch cable.
It would be interesting to get feedback from those with the 2nd generation clutch with hydro clutch?

The hydraulic clutch v/s cable has nothing at all to do with your clutch slipping if either are adjusted correctly.
All the hydraulic clutch or cable is doing is actuating the arm.
The arm is under spring tension to return it to position once you release if everything is adjusted properly.

It is possible for the slave cylinder to be adjusted too tight and cause slippage under heavy load just as would happen if your cable is too tight.
It has nothing at all to do with the hydraulic clutch and pressure plate springs not being compatible with each other though.
If you think about the lever to the arm as one independent system and arm to the push pin as another independent system and the clutch stack as a 3rd independent system its easier to see how each plays their part and interact with each other.

BCS
 

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Yes, it would be a good idea to check the cylinders O-rings as it should be done regularly with brakes master cylinders (usually cylinder maintenance kits are available from motorcycle suppliers). Nevertheless I did not see any oil leak from either the cylinders.
Dommy, if the o-rings or whatever seal they use in them go bad, you won't see an external oil leak. All that happens is the fluid bypasses the seal and you lose pressure. For instance if the seals go bad in the master cylinder, the fluid that is being compressed ahead of the piston just goes by the seal and returns to the reservoir. You would gradually feel the pressure decreasing.
 

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Dommy, if the o-rings or whatever seal they use in them go bad, you won't see an external oil leak. All that happens is the fluid bypasses the seal and you lose pressure. For instance if the seals go bad in the master cylinder, the fluid that is being compressed ahead of the piston just goes by the seal and returns to the reservoir. You would gradually feel the pressure decreasing.
Easy enough to verify, just remove your lower engine cover, pull your clutch lever and see that the arm moves to disengage the clutch. Hold the clutch lever in for a minute or two and see if the spring return on the arm allows the arm to move back toward the clutch engaged positon......if it does not then the hydraulic cylinders are not leaking by.

But even if the seal in the MC was leaking it would prevent the clutch from disengaging....not prevent it from fully engaging causing the clutch stack to slip as the OP is reporting.

BCS
 

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I had a brake line go bad on a car and give me all kinds of issues. I was told it was breaking down but having contaminants could cause a similar issue. It would hold pressure in the line after hitting the brakes. It was a hit or miss problem, and it seemed to be worse after sitting for a while.
 

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I had a brake line go bad on a car and give me all kinds of issues. I was told it was breaking down but having contaminants could cause a similar issue. It would hold pressure in the line after hitting the brakes. It was a hit or miss problem, and it seemed to be worse after sitting for a while.
I've only seen this with rubber lines that were pretty old.
 
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