[2fasst]

Guys I need those with more experience than me chime in on this. I recently installed an EVR basket / clutch pack combo (organic). I measured the stack height with a very accurate caliper and the height is 39.35mm

I have not touched the clutch hydraulics and the system was bled about 2 months ago and worked fine before my recent EVR clutch pack replacement.

I did however install an NGR billet drum and Factory shift kit at the same time.

So the three changes I made are:

1-new EVR 48T clutch basket & organic clutch disks. Height 39.35mm
2-New NGR billet hub/drum
3-FActory Pro shift kit.

Of the three, which one is the likely culprit that causing me NOT able to put into neutral while the engine is running (sitting at a red light)? And I must stress that it's not just difficult to find neutral..I can't put in into neutral..period! Turning the engine off and it drops into neutral easily. Would a 0.35mm too thick of a stack cause this huge of a affect on finding neutral?

The clutch lever is at it's further most position. While in gear at a red light, there is NO forward force that I can feel, if the clutch is still dragging. In fact, if I'm at an incline the bike will actually fall backwards a bit.
Other than that..the bike runs great!

 

[Shazaam]

Difficulty shifting into neutral is due to inadequate plate separation causing drag between the plates. The most common reason for this happening is air in the hydraulic line. The air compresses, the slave piston movement is less than needed, and the plates don't separate enough. Another reason is that larger aftermarket slave cylinders lessen clutch lever pull, but because they separate the clutch plates a lesser amount, they also make neutral difficult to find. A worn clutch pack produces less drag than a new one at a stop, so even though you could find neutral with the previous set-up, you still probably had air in the line.

You need to bleed the line at the master cylinder (system high point - air bubbles rise) to get all the air out.

The correct height of the clutch pack only assures the correct preload force in the clutch springs. It doesn't affect plate separation.

 

[Dennie]

Hi Jason,

I experienced the same thing when I added new plates. However, it was NOT caused by the plates, but due to older oil. I changed it and neutral is now find easy. So it was in my cause a stupid coincidence with the new plates.

You could try to change one steel 2.0mm plate for a 1.5mm thick one. Then your stack height will reduce 0.5mm.

Dennie

 

[ZDM]

Try taking out 1 driven (metal) plate. See if that does anything. Then open up the master cyl. on the perch. There's a small 6 or 8mm screw in there, open it up and burp it a few times. See if that helps. (makes sure you wrap a towel around the MC because it could spray some fluid when you pump it.)
Let me know how the FP upgrade works....curious...

 

[2fasst]

Shazaam, Dennie, ZDM, thanks for chiming in.

I did resolve it. It was definitely the thickness of the pack. I installed a 1.5mm metal disk in place of a 2mm to bring the total stack height down to about 38.8 mm and it finds neutral flawlessly.

I also thought the STM push pin was the culprit so I measured it. The rod sits in the oem push pin 10mm and sits in the STM push pin 7mm. So with the STM push pin I gained 3mm of effective pressure plate clearance (full extension) when applying the clutch.

ZDM, I haven't had a chance to really ride the bike yet other than around the block. I'll give a thorough feedback once I get a chance. During the install, I did noticed the Factory pro unit is better built, with bearings, and slightly larger.

But one thing I'm really impressed with is the design of the EVR 48T basket. With a 12T basket, the only contact points are the 12 sharp 90 degree angle tabs.

With the EVR, the profile of contact points are smooth flowing 'half oval' so the contact point is continuous = lots more contact area. It is much, much quiter (the good kind) but still has the sound of a Ducati dry clutch.

Pictures of the EVR profile:

 

[ZDM]

Thanks, I'm really interested on the FP kit. Although since FBF replaced all the bearings in my lower end, re-shimmed everything.... my engine is markedly smoother and does shift better. I'm not sure the FP kit would improve much, but I like to tinker with this stuff and the kit is inexpensive and looks relatively easy to install.
I've considered going from a DP 6-spring slipper back to a standard clutch unit so the 48T basket is definitely a future choice. My slipper works well but all in all it's just not needed for the street. However the 48T clutch packs are pricey.

 

[2fasst]

Update:

Problem NOT solved.

So let me update some info.

Hydraulics (mastercylinder/slave) was bled (REALLY well) a short while ago and was working perfectly before this recent install. So I think it's safe to assume I have no air.

-New EVR 48T basket/clutch pack. Roughly 39.3mm thickness
-New NGR drum. Verified the offset (where it sits against spacer on the engine side) is same as OEM. So the clutch plates sits in the same location/distance from spacer as OEM in the basket
-New STM clutch pushrod pin. 3mm more shallow than OEM. So now clutch pushrod is recessed 3mm more into slave cylinder (you can think of this as having a pushrod that is 3mm longer than OEM)


REUSED parts:
-Yoyodyne slave cylinder. Can't remember size. I think 29mm
-Reused CycleCat pressure plate
-Reused Speedomoto springs. Measured to be 39mm


Symptons:
EVR pack at 39.3mm...shifts great and no slippage. But can't find Neutral!

Replaced one 2mm metal disk with a 1.5mm and I can find neutral, but clutch slipping in all gears.

At this point is it safe to assume that the reason for the slippage clutch is that my pushrod is too long? Although the slave is able to take up some/most of the slack?

Difficulty finding neutral may be a separate problem (sticking clutch plates, Factory Pro shift kit)?

 

[mpaschetto]

Update:

Problem NOT solved.

Hydraulics (mastercylinder/slave) was bled (REALLY well) a short while ago and was working perfectly before this recent install. So I think it's safe to assume I have no air.

2fasst,

Don't assume anything....spend five minutes and rule this out!
Re-bleed the system, and you will know for sure if this is the culprit.
Be sure to 'burp' the bleeder at the master cylinder first.

 

[Dennie]

IF some air would be in the system, you could ad a zipper/ ty rap over the master and leave it for a night. After the night, ONLY bleed the master by opening the upper 6mm bolt and push the master slowly by hand. If some air was still in the system, it will come out.

You could also bleed the slave with a different procedure (my former bike, the Aprilia RSV Mille R needed bleeds often). Lose the bleeding valve and close it by hand. Remove the slave and make sure the cylinder itself stays in the slave. Now rotate the slave with the bleeder valve positioned to the highest point (slightly backwards under an angle). Then open the bleeding valve and push the slaves cylinder back by hand. Then close the bleeder and push the clutch master slowly until the cylinder comes about 10mm forward. Repeat the above named cycle a few times to be sure.

 

[2fasst]

Hey guys so I've re-bled the system to bring it out of the equation (and make you guys happy ). Trust me when I say that I have no air in the system. I gone through a huge container of brake fluid at both the MC and slave. In addition, the hydraulics worked fine prior to this clutch upgrade.

I'm beginning to think more strongly that the STM pushrod pin (being 3mm shallow) is effectively making my clutch rod 3mm longer. My slave may be able to take up most of the increased length, but maybe not all. I will re-measure how far the clutch rod must protrude out the clutch side while maintaining full pressure plate force. Then I will check the other side to see how much of the rod is exposed and how much the slave cylinder can handle.

This is only to find out why a 0.5mm reduction in clutch pack thickness is causing my clutch to slip. My OEM worn out clutch pack is a fulll 1.5mm thinner, and had more grip/friction. I also upgraded the STM pushrod pin at the same time so beginning to think that is the problem.

The difficulty to find neutral may be a separate issue. I'm beginning to think the 'super tight fit' of the EVR clutch plates again the new basket is causing my plates to stick together, and not separating properly when I apply my clutch lever

 

[ProphetPVD]

Hey guys so I've re-bled the system to bring it out of the equation (and make you guys happy ). Trust me when I say that I have no air in the system. I gone through a huge container of brake fluid at both the MC and slave. In addition, the hydraulics worked fine prior to this clutch upgrade.

I'm beginning to think more strongly that the STM pushrod pin (being 3mm shallow) is effectively making my clutch rod 3mm longer. My slave may be able to take up most of the increased length, but maybe not all. I will re-measure how far the clutch rod must protrude out the clutch side while maintaining full pressure plate force. Then I will check the other side to see how much of the rod is exposed and how much the slave cylinder can handle.

This is only to find out why a 0.5mm reduction in clutch pack thickness is causing my clutch to slip. My OEM worn out clutch pack is a fulll 1.5mm thinner, and had more grip/friction. I also upgraded the STM pushrod pin at the same time so beginning to think that is the problem.

The difficulty to find neutral may be a separate issue. I'm beginning to think the 'super tight fit' of the EVR clutch plates again the new basket is causing my plates to stick together, and not separating properly when I apply my clutch lever

Bleeding is not the problem... you were on the right track earlier attacking the stack height issue, which I suspect most likely IS caused by the pushrod pin. If you remove 2 more 2mm plates, and replace them with 3 1.5mm plates, you will essentially add .5mm to your stack, and the new height will be 39.3mm. I would go this route of stack height modification via plate swaps. Follow with a test to see if the feel is where you want it, and then modify again if necessary.

 

[davy.j]

Something here is dragging.

First make sure you have the lever far enough out for sufficient master cylinder piston throw.

Then check all the plates are flat on a piece of glass with feeler gauges and re-face any buckled ones or any with high spots on the glass with wet and dry paper and washing up detergent as a cutting fluid.

Don't tell me they are new... even new ones can be dished/warped.

Wash all the plates in strong detergent before refitting. and if your brave enough give them all the Tom Tom lithium grease treatment

If you have a convex plate remove it and replace with a flat steel one and then reset the stack height to std.

I'd also replace the throwout bearing (std, SKF 7201 or delux, B7201 2RS angular contact thrust type like I use)

Once you have it all working properly and if your brave enough give them all the Tom Tom lithium grease treatment to finish the job off for a really smooth unit.



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[2fasst]

Something here is dragging.
Have you checked all the plates on a piece of glass to make sure they are all perfectly flat and not slightly buckled?
Re-face the steel plates on a piece of wet and dry on the glass sheet to get rid of high spots and discard any dished ones.
If you have a convex spring plate, remove it and fit a flat one instead and reset the stack height to normal size.
Check the thrust bearing is good too.. infact they are so cheap just replace it.
(SKF 7201 or if you are really keen B 7201-2RS angular contact thrust type)
.

Awesome idea davy..I haven't checked that. And I'll reface. So just place a piece of sandpaper onto the glass?

 

[Shazaam]

Dished Clutch Plates

I'm a big fan of Ducati's dished plates, here's why.

During acceleration the clutch is prevented from slipping by the frictional force between plates. The higher the torque output of the engine, the more frictional force that is required. In order to get more frictional force, you need more force to push the plates together. The force holding the plates together is determined by the compression of the clutch springs, which in turn, is controlled by the stiffness of the springs and the amount that they are compressed, i.e. the height of the clutch plate stack.

There are two values of frictional force that can exist between the clutch plates: static and sliding. The coefficient of static friction is always higher than the coefficient of sliding friction.

Smooth progressive clutch engagement requires that the force transition between sliding and static occur gradually, and this is why a curved dished plate is placed in the clutch plate stack.

When the clutch lever is released, the push-rod moves the pressure plate, which in turn moves the slipping plates together, transmitting increasingly higher torque to the rear wheel. At some point, the force between plates is sufficient to cause a transition between static and sliding and the difference in the two coefficient of friction results in an abrupt change in torque output. The clutch grabs suddenly.

To minimize this suddenness, a dished plate is added to the plate stack. A dished plate is essentially a spring that exerts a force between the plates when it becomes flattened so as to give a more progressive force between plates than can be achieved using the stiffer clutch springs.

 

[davy.j]

Yes just a thick sheet of glass on a flat surface (I use a sliding cupboard door on the kitchen table) with P80 grade paper (don't worry about getting them too smooth)

.

 

[davy.j]

I'm a big fan of Ducati's dished plates, here's why.

I love the theory behind them but never had any real success with them and the disadvantage has always outweighed the benifits for me.
And with the lithium grease treatment the clutch has a very smooth progressive uptake naturally.
I find unless the dished plates are lubricated they dig in on their outer edge and eventually make a groove, bind in it and often make a scraping noise as they flex. ( you nearly always find a rust mark around them after a while where they constantly scrape the next surface)
To me they just add an unnecessary extra level of complication plus heat eventually destroys their temper and they loose their set making them ineffective.
Come to think of it I don't really like the theory behind them as it is flawed... the clutch needs the coils spring pressure to overcome to dished spring pressure to achieve full engagement so in reality it just takes away from the coil spring pressure and takes up space that can usefully be occupied by a working driving plate.

.

 

[ttpete]

I'd also replace the throwout bearing (std, SKF 6201 or delux, B7201 2RS angular contact thrust type like I use).

You're the only one that has mentioned the 7201. I also decided to use one. Anyone who is going to install a 7201 needs to understand that it has to be installed the right way round. The inner race has a larger flange on one side, and that side should face the clutch plates.

 

[ZDM]

Loads of different manufacturer parts being used in this clutch. Can the EVR basket be used in conjunction with the NGR hub? Do you have an OEM hub to replace the NGR?
I would start removing stuff until it starts working properly again. Go back to square one. I would start w/ removing the FP kit first-
The issue w/ the FP shift kit is it's new, while everything else is old. If there's one thing I learned from FBF it is to be careful fitting new replacement parts with old in a Ducati(when possible) These parts obviously start to wear TOGETHER, mixing new parts w/ old might just be throwing off spec tolerances enough to cause a problem.

 

[2fasst]

Ok update (and more help needed) guys. Sorry it's a bit lengthy, but lots of info to update.

The clutch slipping was caused by the STM pushrod pin being 3mm more shallow than the OEM unit (as there's a small ball bearing inside the stm unit), which the Yoyodyne slave cylinder didn't have enough depth to handle the extra pushrod length. This caused the pressure plate not being able to clamp down on the clutch disks. This has been corrected.

In 1st gear, and clutch lever pressed, the bike wants to pull forward indicating that there is clutch drag.

I found that I can put into Neutral if I really loosen the springs (just as a test).

I also noticed that when I squeeze the clutch lever, the pressure plate does not move away from the disks evenly, as an example: most areas of the pressure plate move away from the clutch disks 2mm, while one particular area only move 1mm.

So here are the questions for you guys:

1-Is the uneven pressure plate movement caused by the uneven spring tension? I measured all of them to be 39mm uncompressed. They are Speedymoto springs.

2. I'm using a Brembo billet 16x18 mastercylinder and a Yoyodyne 28mm slave. How do I get more separation between the pressure plate and the clutch disks? Clutch lever adjusted to the farther most position, system has be bled,bled,bled, and clutch stack height is 39.3mm.

I've changed the stack height to 38.8mm just for kicks. But changing stack height, as Shazaam indicated early on, will not change how much the pushrod/pressure plate moves as this is determined by the masteryclinder/slave ratio. Changing the stack height will only change the spring preload.

Does a 27mm slave cylinder exist?

 

[2fasst]

And with the lithium grease treatment the clutch has a very smooth progressive uptake naturally.

Come to think of it I don't really like the theory behind them as it is flawed... the clutch needs the coils spring pressure to overcome to dished spring pressure to achieve full engagement so in reality it just takes away from the coil spring pressure and takes up space that can usefully be occupied by a working driving plate.

.

Davy.j, I have yet to try your recommendation of removing the dished dishes and replacing with standard flat ones. Thinking about it..the dished plates may actually decrease my pressure plate to clutch disk gap. Because the dished plates will 'expand' as the pressure plate is moved out. Thoughts? Am I on the right track thinking it that way?