Evoluzione slave question/problem

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by OldnoGPS, Apr 28, 2007.

  1. OldnoGPS

    OldnoGPS Just a sightseer

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    I received my new Evoluzione slave cylinder, installed it, bled it, hopped on the bike for a ride and - nothing. Clutch action feels normal. When I put the bike in gear and let the clutch out it didn't move. At all.
    Before I go any farther: The Evo unit is very nicely made, good instructions, comes with a new banjo bolt, bleeder nipple, crush washers and spare o-ring seals. I've read good results from others using this slave, so ??
    Back in the garage, rebleed to be sure, same result. On the centerstand I can put it in first, let the clutch out with the rear brake on and - no clutch action, engine keeps running. Took the slave off, compressing the piston sends fluid back up to the master, squeezing the lever makes the slave piston move out just as it should.
    Started the bike with the slave off entirely (clutch rod "free" - at full extension). Gronk into first, hit the rear brake and the engine dies. Clutch itself is fine, which makes sense since it was fine yesterday. (Stock slave is leaky).
    Took the plastic spacer off and installed the slave so I could see if it looked like the slave was compressing the clutch rod (not with the lever pulled). Maybe about a mm or so. Hmmm. Goes in and out when you pull the lever. Hmmm. Removed slave again.
    Compared Evo to stock unit. Stock slave allows piston to retract farther back into its bore than the Evo relative to their mounting flanges. Maybe an o-ring in the Evo came off and won't let the piston compress fully? Nope. Disassembled Evo, both o-rings in place (stock has one wimpy little o-ring, Evo has two fat boys). Evo piston is, of course, larger to accomodate the extra o-ring. Piston retraction is limited by this extra depth (thickness) of the piston and the fact that the shift lever limits external dimensions of the cylinder.
    I've eliminated the 5 or so bolt-on, take-off steps trying to figure out WTF is going on. Long story short, Evoluzione slave doesn't work on my bike. I replaced yet another o-ring on my stock slave piston, re-installed it, bled it and the clutch works just like before - about half-assed and draggy, snatchy on downshifts, which is why I bought the Evoluzione. I know this is because it needs to be bled some more and/or it's sucking air around the piston/o-ring interface - which is why I bought the Evo.
    My question to the forum is: My bike is an early '04. Supposedly, the clutch rod upgrade was done. The dealer that was supposed to have done it also supposedly did the head bolt TSB's. Another dealer ACTUALLY did the head bolt TSB a couple of thousand miles later, so KTM got to pay for it twice. That considered, I suspect the clutch rod may be different (never done), that it's a different length on the early bikes than what Evoluzione designed the slave for, or something along those lines. I can only assume that the Evo slave is compressing the clutch rod just enough so the clutch stays released, which explains why there is no engagement. Has anyone else had this problem or have any thoughts?
    Thanks,
    Ted
    #1
  2. ABYSS

    ABYSS KTM

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    you contact Ken @ Evoluzine?

    GONOW was the test bike and his is a 2004 adventure as well.

    You way want to PM him and get his input.
    #2
  3. YOGOI

    YOGOI Prick

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    The old clutch rod was aluminum w/ a stainless steel or titanium tip at the slave cylinder side. The updated (i hate call'n it that) rod is black steel. Also, the old one was a 3 piece rod and, the steel part will disconect from the rest of the rod if you pull on it. So long story, you should be able to see if you have the old or new rod when you have the slave cylinder off.
    #3
  4. K2m

    K2m ....58....

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    The rod is not coming out far enough. Put two washers, one either side and try it. Add washers if necessary until it works. Then you will know how much to cut off the rod, but then the rod is no good for any other slaves

    The rods will be the same size, otherwise there would be more problems. This adjustment is critical. There must be a problem with the machining of the slave. Ring Ken and have it replaced. If you need your bike just leave the washers on until the new one arrives.
    #4
  5. GoNOW

    GoNOW Long timer

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    According to YOGOI's description, I don't have the clutch push rod TSB done. My dealer is not very good with computers so I have not asked them to lookup my bike. I have just been doing the TSB myself.

    I don't recall the push rod TSB having anything to do with replacing the slave cylinder, or the plastic base. If that is the case, then the new rod should be the same size and the Evoluzione one should fit. Call up Ken. Something is wrong.
    #5
  6. OldnoGPS

    OldnoGPS Just a sightseer

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    Thanks for the replies. I'd call up Evoluzione but it was Sat evening when I had the problem and I doubt anyone is there.
    SST (previous owner and buddy) e-mailed me to say he's quite sure the pushrod was updated. He bought the steel one, dealer handed him back the alum one after the work was done. It looks like steel, so I'm assuming now that it's the correct rod. Next time I pull off the slave I'll throw a magnet on it.
    Let me clarify (and my apologies, I'm not a tech writer):
    The clutch works "fine" with the stock slave. When it's properly bled (between hourly failings) the gearbox downshifts nicely and the clutch doesn't exhibit any signs of drag.
    When the Evo slave is installed, it's apparent that the piston is bottoming out in the slave's bore and compressing the clutch rod. This, of course, is releasing the clutch, which is why I have no engagement despite having lever travel/slave piston travel.
    The stock slave allows probably 4-6mm of additional piston retraction into the bore compared to the Evo, which is allowing the rod to fully extend and engage the clutch.
    I think I could try a washer between the plastic spacer and slave (or plastic spacer and engine) to space the slave one or two mm farther away from the engine and gain full clutch rod retraction. That will likely require grinding off some of the inside of the shift lever, there is very little clearance there.
    I assume the clutch rod gradually moves farther left (sticks out of the engine more) as the clutch pack wears and gets thinner. This would indicate that the Evo slave may limit the available clutch wear point, working fine on a new or near new clutch, but not allowing sufficient clutch rod retraction on a clutch pack with more miles. Since my bike at 30K on the original clutch works with the additional available piston retraction of the stock slave, that's the best theory I can come up with.
    I may try some additional fiddling later today. Or set fire to the bastard.
    (950 is presently my only transportation, I paid $27 extra to get the Evo slave here ASAP so I wouldn't have this problem).
    Ted
    #6
  7. GoNOW

    GoNOW Long timer

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    Call him up. You never know if he will be around.
    #7
  8. K2m

    K2m ....58....

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    Just add washers, so you can use it, don't grind anything. contact Ken.

    Remove the sprocket cover, leave it of as it will get in the way of the washers.
    #8
  9. DockingPilot

    DockingPilot Hooked Up and Hard Over

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    I say wait for Ken's response.
    #9
  10. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    Too bad Revloc doesn't make a clutch for the nine-fiddy :evil
    #10
  11. OldnoGPS

    OldnoGPS Just a sightseer

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    Thanks again to everybody for their input.
    I'm low on mineral oil after all the bleeding and swapping back-and-forth of slaves, so I'm not going to be able to re-install the Evo with washers and try it until a) the dealer opens on Tuesday and b) I can borrow a car to get to town to the dealer.
    I hope to have time today to unbolt the almost-working-with-a-new-o-ring stock slave (leaving the hydraulic line on it) and re-install the Evo temporarily with shimming washers to see if it will clear the shifter.
    #11
  12. OldnoGPS

    OldnoGPS Just a sightseer

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    Morning update:
    I carefully bled (and backbled) the original slave with it's new o-ring. Seemed to be working fine.
    Went for a ride, downshifts fine, no dragging. Of course it upshifts ok. Rode it 30 miles, still OK when I got home.
    I checked the Evo against the original (original unbolted) before I did the bleeding. The Evo does indeed bottom out it's piston pushing against the clutch rod before the mounting flange reaches the mounting surface. (You can look down the hole with the banjo bolt removed and see the rear of the piston). In other words, when it is mounted it is compressing the rod and causing the clutch to release. Just verifies that installing a washer at each mount to space the slave out form the engine may make the Evo work.
    At the same clutch rod extension the stock slave still has some room to move it's piston back into the bore.
    I need more Motul mineral oil before I can re-install the Evo to check that theory. No, I don't have any 2 weight fork oil either.
    #12
  13. evoluzione

    evoluzione Been here awhile

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    ted,

    first off, i'm sorry you had a problem with our slave cylinder. in the future, if you (or anyone) has a problem, please don't hesitate to email us or call (and leave a message). i check our email over the weekend and i will usually check for messages as well.

    back to the issue. it sounds like you're saying the piston on our slave cylinder does not allow the clutch to engage. since the stock unit works, this would imply that the bore in the center of our piston is not deep enough.

    now, the depth of the bore in our piston is actually 2mm deeper than the stock piston (to allow more freeplay) so something else is wrong. the only other thing i can think of is machining error. if you look in the bore of our piston, you should see two diameters - the first is 8mm and then deeper down is 6mm. do you have dual bore sizes? do you have a set of calipers? if so, measure the total depth of both bores. ours should be ~14mm and the stock piston is ~12mm.

    please let us know what you find and we will try to help get this resolved.
    #13
  14. PowerCell

    PowerCell Manufacture Super Supporter

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    +1
    #14
  15. OldnoGPS

    OldnoGPS Just a sightseer

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    Ken,
    Thanks a lot for the response. I had measured the bores before and saw that you had allowed about 2mm more depth in the bore that engages the rod than the on-center measurement to the original slaves' piston ball. Your slave depth is indeed 14 mm to the very bottom.
    I have a new theory that I think may explain what's happening:
    My clutch rod isn't perfectly centered in the bore that exits the engine and that, of course, means that it isn't centered in the slave piston. Because of that, I now think that the rod may be engaging the step in the Evo piston bore rather than going all the way to the bottom. That step is about 9mm deep rather than the 14 to the bottom. If it's hanging up there, that would more than account for the amount your Evo appears to be preloading the clutch rod.
    That said, I have no idea why the clutch rod isn't centered. It's quite firm where it rides, maybe it's bent? It appears to be the correct replacement (steel) clutch rod. I know the PO never had it apart and had the dealer do the rod upgrade. I've never had the slave off until the recent spate of leaking/bleeding, etc. and that's where it was when I first saw it. It isn't so bad that I figured it was a problem (still fits easily into the relatively narrow piston rod engagement bore) So, should the clutch rod be a little loose and rattly in it's hole?
    Whatever the answer, it's nice to know that you have a sincere interest in helping me figure out the problem. To all reading: besides the good customer service here, I e-mailed Evo Friday to get a tracking number for my slave as it was getting late in the day. Not only did they supply it, they e-mailed with the info about where it was enroute and that it should be dleivered as scheduled (it was - UPS was way later than usual), as well as the tracking info. I said before that the parts are top quality with good instructions, new banjo, new bleeder, spare seals, etc. Thanks to Ken and other Evo employees for providing a nice product and giving a damn whether it works as intended.
    Ted
    #15
  16. cpmodem

    cpmodem Orange Caveman

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    Ted and Evo are, indeed, good folks. Very atune to the needs of their customers. This is a rare thing to find these days.

    It sounds like there is somethind wrong with your pushrod. Possibly on the clutch side. Good news is its pretty easy to check. Just remove the clutch cover (the small round one, not the whole rotor cover). Then remove the six springs on the pressure plate. The pushrod is retained with a through pin on the slave cyl side. Remove the pin and the rod will slide out the clutch side. Let us know what you find.
    #16
  17. evoluzione

    evoluzione Been here awhile

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    ted,

    not sure about the pushrod but if it is slightly bent, that would help explain why your stock slave cylinder is leaking (the pushrod centers the piston/seal on the stock unit).

    our slave cylinder has a total of 2mm less allowed travel than the stock unit (due to the bigger piston and dual seals). based on the info you've provided, your stock slave cylinder piston should be just bottomed in the bore of the cylinder - is it? if that is the case, i would guess that there is something worn on the clutch hub or pressure plate since the stock unit should have had at least 4mm of clearence before bottoming out.
    #17
  18. OldnoGPS

    OldnoGPS Just a sightseer

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    The plot thickens, just came back in from the garage. My pushrod isn't really bent, it's just that the chain guard tends to spring toward the rear when the slave is unbolted, which makes it appear that the rod isn't centered. I cannot make the rod "hang" on the smaller bore diameter's edge as I thought so that isn't the problem. The Evo needs 5 mm from touching the rod (bottomed out in the bore, checked many times to be sure) to pull up to the mounting flange. Putting the Evo in the vise and compressing the piston (stiff spring in there and I needed to measure) only shows 4 mm of available travel. That's about the original one mm I was guessing that I needed/that it's compressing the rod. FYI - this rod has been in the bike for about 16,000 miles without a problem (it's steel, hit it with a magnet). Measuring the original slave's available retraction requires that I mess with the functioning, bled cylinder. It's dry around the piston and I can ride the bike like it is (after I bolt it back on). I'm sure I have a mm or two of free play in it.
    #18
  19. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    Just slightly off-topic...I'm pretty sure that hydraulic clutches on the newest KTM MX/offroad bikes have migrated over to using brake fluid, like the Hebo units that GasGas uses (for lighter lever effort). Do new 950's/990's still use mineral oil or have they been changed as well? Just trying to get a clear picture in case I get a little nuts and buy this thing...:D
    #19
  20. evoluzione

    evoluzione Been here awhile

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    the 950/990 systems still use mineral oil.
    #20