New Dry Clutch Plates/Basket/Hub - Won't Disengage ??? - FIXED

[junior varsity]

I fear I have messed something up. My bike will not disengage the clutch. The lever goes straight to the bar after riding with zero effort, but returns fine when I let it go, if I pump repeatedly like a maniac I can get enough pressure in the line to finally disengage the clutch. Ride for another few minutes, and I'm out of luck again.

The line has been bled, by me, multiple times. I just took it to a mechanic, and he did the same. Then went on test-ride, and experienced the same problem.

Here's the setup:

Barnett Clutch Pack, Red friction material - new
V2 Hub - new
V2 Basket - new
Evoluzione Slave - had this for years
STM Pushrod Pin - had this for years
Brembo "GP" Radial Master - had this for years
Stainless springs, Rizoma pressure plate - had this for months

Where am I having problems? I installed the plate pack per instructions, starting at back: S, S, F, S, F, S, F, C, F, S, F, S, F, S, F, S until I ran out of plates (can't remember the exact # of friction (F) and smooth (S), but the curved plate (C) went in the very middle, and there were two S at the bottom of the basket, and the top plate was S).

Please help, I'm about to depart on a long adventure! I need to be able to shift gears and come to a stop without the clutch still engaged and pulling the bike forward, making it stall!

[CairnsDuc]

If I hear something like this from Customers, the first thing I do is point the finger at the Slave cylinder, I've seen so many OEM unit's fail, and your fault matches that description very closely (yes, I do notice you have a aftermarket Slave) That would be the thing I would be checking first.
Hopefully someone with much greater Dry clutch knowledge will be chiming in soon to assist you.

[OverCaffeinated]

I'm not an expert, but try reading this page.

http://www.desmotimes.com/product5.htm

Also, if you still have your oem slave, I would try reinstalling it to rule it out as being the problem.

[Slide Panda]

I fear I have messed something up. My bike will not disengage the clutch. The lever goes straight to the bar after riding with zero effort, but returns fine when I let it go, if I pump repeatedly like a maniac I can get enough pressure in the line to finally disengage the clutch. Ride for another few minutes, and I'm out of luck again.

The repeated pumping puts me in camp with Carnis.  It sounds like you're losing pressure in your hydraulic system, or have a nasty air bubble.  It doesn't sound to me like something to do with your new clutch parts.  It might have been an existing problem, that was exacerbated by the new kit - for example the new clutch pack is a bit taller than the old one requiring more clearance from the pressure plate to disengage. 

I'd bleed again... very slow and purposefully - and then leave the lever strapped to the bar over night.

[silentbob]

Don't forget to bleed it at the master, not just the slave.

[junior varsity]

Problem resolved!

OK, so the most typical issue (bleeding) was not it at all. I had bled at the bottom and top and repeated numerous times, even using a mightyvac. I took it over to Stuart Rust's shop (Rust Restorations) and we had a look at it together. He took it out for a ride, and had the same problem. I'm honestly not sure how I'd been getting by in the past...

My clutch pushrod (a 1999 M900 remember) is 225mm long (or thereabouts). The newer style (00+) are slightly longer, at 233mm.

The stock pushrod was not fully seated in the slave, so it could rock back and forth, and the cylinder had to move out considerably to hit the rod at all.

On the other end, at the pushrod "cap" or as STM calls their replacement a "pushrod pin", the captured bearing inside the STM pushrod pin had frozen, and had begun drilling (for lack of a better word) into the push rod.

SO, several things got replaced:

Evoluzione Slave Cylinder (old) is off the bike. It might not have been a problem, but had suffered significant wear. Replaced with Ducati Performance (that's what AMS had in stock). A little spendy, but dammit, its the last time I have to replace that sucker, I hope.
Clutch Pushrod - Replaced with longer style, which I was lucky to find in stock at AMS as well.
Clutch Pushrod Cap - time to throw out the STM one that has a bad bearing in it.
Clutch Pressure Plate Bearing - Might as well replace it while everything is apart.

Stuart looked at me and said "Its nothing you've done that made it quit, your bleeding was fine. And its not the new clutch. I'm surprised its been working very much all along. Its this old slave cylinder you put on because you've got girly hands"

Things to learn from this experience: The only difference between the older slaves and the newer slaves is that the require longer push rods. They bolt up to the same 3 holes. They do the same thing. One needs a longer pushrod to seat into the piston.

The repeated squeezing of the lever once the pressure was lost was just putting more fluid down into the slave to move the cylinder further out. So that solves the mystery. Its was like damn Scooby Doo.

Other things of note, I do not have girly hands. That is just a fallacy. I have big burly man hands. Not quite sausage fingers, but I'm a large mammal.

[ducpainter]

<snip>

Stuart looked at me and said "Its nothing you've done that made it quit, your bleeding was fine. And its not the new clutch. I'm surprised its been working very much all along. Its this old slave cylinder you put on because you've got girly hands"

<snip>

I like this Stuart.

[junior varsity]

He's really great - used to work at AMS and traveled with Jeff Nash back in the racin' days. Rust Restorations - Specializing in Ducati, Triumph, and Norton bikes. He had a good laugh and let me know that "you monster owners are all alike, changing things from the factory, often making things worse!" (Imagine with New Zealand accent). He's great fun.

[ducpainter]

He's really great - used to work at AMS and traveled with Jeff Nash back in the racin' days. Rust Restorations - Specializing in Ducati, Triumph, and Norton bikes. He had a good laugh and let me know that "you monster owners are all alike, changing things from the factory, often making things worse!" (Imagine with New Zealand accent). He's great fun.

Like I said, I like his thinking.

Change is not always good.

[junior varsity]

I'm learning that. Just because there's a way to change it, not necessarily a good idea to do it.

[billruiz]

I've been wanting one of them fancy clutch slave thingies, but now that I've been going to the gym for three months the clutch doesn't seem so bad. On the minus side, my Yamaha always feels like the clutch needs to be bled.

[erkishhorde]

FYI, if you had gotten a Yoyodyne slave it comes with a little pill to extend the old short pushrod to the proper length. It also has a lifetime warranty so if it had worn out or you happen to have gotten some drilling because the throw out bearing freezes you'll either get a free replacement or 50% of a replacement depending on the damage.

[♣ McKraut ♣]

i think my favorite stuart quote from last saturday was "it's never fun being in a dry hole" in reference to the forks and oil...

[junior varsity]

That was really good. I should have expected it, but it was a surprise anyhow.