790 Reported Clutch failures - My 12k mile examination

Discussion in 'Parallel World (790/890)' started by windblown101, Nov 10, 2019.

  1. justinope

    justinope Long timer

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    Gotcha, sorry for the misread of intention! I'm all for giving as much info as possible to help figure this out, but I also think I've just become so angry at the situation I can't provide any valuable input anymore :(
    #41
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  2. Toddv

    Toddv Been here awhile

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    I get! Really
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  3. kubcat

    kubcat Been here awhile Supporter

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    It's an interesting point that you raise. I suspect that the actual percent of failed clutches is very small, so it's unlikely to be a design flaw that KTM should fix. I agree that, especially if the numbers are small, KTM would get much more goodwill out of replacing them for an infant mortality situation, but I can also clearly see why they would take this position. I think this might be the reason most people react as they do. I don't see it as being a KTM apologist, I see it as being a pragmatic realist who has a grasp of the real business costs that drive warranty policy. Believe it or not, the loss of your good faith in them IS weighed against the impact to the income statement in all well run companies. It is a textbook example of a calculated risk that makes economic sense to take.

    People really need to try and understand that it is more important that the company is well run and stays in business than having them meet every customer request no matter how it may impact the business. Otherwise we'll end up like the Buell owners groups.
    #43
  4. sideup

    sideup Been here awhile

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    My wife has a 790s with no problems but mainly has been used on the street. After selling my 1090R, I am on a waiting list for a 790R. This clutch issues reminds me of the rocker arm issue on the 690's with the same typical KTM response. I haven't changed my mind yet but I know like the 1090R air boxes the 790 will need special more frequent inspections or aftermarket parts to correct issue.

    KTM is for the most part is blaming the users for clutch abuse. One item is did read on a UK forum is Laia Sanz had a clutch replacement in the Bosina Rally.
    Quote: " Laia Sanz's clutch had to be replaced at the Bosnia Rally. Laia is a thirteen-time Women's Trial World Champion, so you would expect SHE knows how to use a clutch."

    Post: https://www.ukgser.com/forums/showt...90-Adventure?p=5530621&viewfull=1#post5530621
    #44
  5. bobnoxious67

    bobnoxious67 Baby steps...

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    Curious to know what her TC level was set to...
    #45
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  6. [Art]

    [Art] Been here awhile

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    I could not find a source for this affirmation about Laia Sanz. And in a race situation, if you ride a factory bike, I would not be surprised if the bikes mechanics changed the clutch everyday anyway…
    #46
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  7. keener

    keener Speed changes you.

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    I think the clutch adjustable could be the source of these clutch failures and it's not the owners fault. It's the dealer that should adjust the clutch correctly before delivering the bike. May be KTM has not put on the pre delivery to do list for them, who knows.

    I noticed pretty much in every case of catastrophic clutch failure, the report says : I was riding normally when I noticed the slack on the clutch leaver was greater than usually. (Clutch plates have been slipping under load most likely during high speed accelerating which puts the most stress on the clutch pack. At this point plates are super hot and are wearing rapidly). Then they say I pulled over and took up the slack by adjusting the cables as per th manual! Off I went for another 50 miles and my bike blew up.

    What's happening during that 50miles is that the hot plates were forced to take the load and wore even more, they got so thin that they broke and the rest is just not pretty. One old trick to get home with a worn clutch is to use a leather shoe string like a ring between the plates, but that's a different matter.

    The cable clutch adjustment in combination with smaller than usual clutch pack is the cause of these failures. That's my theory. I may be wrong, may be it's an oil supply issue. But in my experience the 0.05mm(0.25 vs 0.30) of jet size shouldn't make such a big difference.

    Having slightly more slack on the cable doesn't hurt. Not enough slack will cancel out some of the initial pressure the pack needs to see to live up to its maximum grip it can deliver.

    Here is a short video I took the other day, while test fitting one of our new up coming parts for 790:

    #47
  8. CalamariKid

    CalamariKid Been here awhile Supporter

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    Given the above, would a Rekluse Torque Drive clutch be a good way of compensating for this?
    #48
  9. gearheadE30

    gearheadE30 @LC8Adventures Supporter

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    Adjusting and maintaining clutch free play and being conscious of minimizing slip would be a good way of compensating for this. No need to throw more parts at it. There have been a few reports on the internet, but I have not seen any reason to believe this is anything but a few people with poor clutch control skills or didn't know how to adjust a cable clutch, and a few people who got unlucky and ran into early manufacturing defects. Clutch failure, at least so far, is far from a common problem and is not something I'd go out of my way to worry about if you've got passable clutch control skills and keep an eye on that adjustment.
    #49
  10. brianbrannon

    brianbrannon They'll ride up with wear

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    Yeah let's get rid of traction control and ABS and cruise control and windshields so we can feel manly again :csm
    #50
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  11. AdvRonski

    AdvRonski They call me......Ronski

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    Here's an interesting article about the issues and fixes for slipping clutches on the Kawasaki 400 Ninja, which uses the same design as the 790 clutch. 3 things stood out to me, the first being that the clutch release shaft will bottom out in the mainshaft after a very small amount of wear to the clutch pack, and 2nd, that they add an external spring to the lower end of the clutch cable to ensure the release arm isn't taking up any clutch spring pressure. The 3rd item is their assessment of the general action of the clutch, which also has a narrow engagement zone. They say it's because as you are starting to feed power when the clutch is partly engaged, the slippage engages the ramps on the pressure plate, essentially overriding your slower release of the lever. Their fix is stiffer springs and a modified release shaft that allows more clutch wear before bottoming out. I think I may have to take another look at my clutch, and measure when the release shaft bottoms out on the 790 motor.

    https://www.norton-motorsports.com/...trals-and-dropping-gears-explained-and-fixed/
    #51
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  12. TrailTrauma

    TrailTrauma Nemophilist

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    Hence Birchy installing heavier springs in his 790 clutch?
    #52
  13. justinope

    justinope Long timer

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    As someone affected, I tend to disagree.

    I still have no idea how to decide between Rekluse TorqDrive or a replacement OEM pack myself. I can't be sure it was an early manufacturing defect, an oil jet sizing issue, etc etc. I know for a fact my free play was set correctly at all times and that I do actually know how to ride a motorcycle (looking at my other high mileage bikes with 0 clutch issues, both cable and hydro alike).. Either way you look at it- I could be looking at having to rebuild my clutch pack every 3-4k miles and thus far no solution to the problem exists. If I replace Rekluse I probably gain longevity. If I replace OEM, maybe KTM cares more in 3-5k miles when the new one burns up? (but I highly doubt it) The downside to OEM being they could disintegrate apparently and take my engine down with them.

    Telling others it is not a common problem is really infuriating to people like me who are still waiting for KTM to own up to the problem and figure out the root cause / issue some type of fix. It reads like you are giving KTM a pass on a problem there is no solution to, aka KTM 690 Rocker Arms v2.0 (except ~3-5k miles until potential grenade instead of ~10-15k).. Epecially when it is really easy for me to believe the problem is much more widespread. For example, I have quite a few stories online and in the FB groups, then figure you can multiply that number by 2-4x to cover the owners who aren't active on forums / social media. So thats probably around 50-150 affected owners?

    Something I don't think many know is that Rekluse is collecting data on the issue and are considering offering a kit that includes their TorqDrive pack and an enlarged oil jet with the tool to change it out, etc as a potential solution to the problem.. At the least I'd imagine their disks (with steel cores) won't grenade and cause rebuilds.

    My overarching feeling so far with the bike is disappointment at how little KTM cares about supporting their new models. Which is sad because up until this bullshit I was loving it and KTM equally.
    #53
  14. kubcat

    kubcat Been here awhile Supporter

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    I'm sure that it is infuriating, and I would feel the same if I were in your shoes. However, your infuriation does not make it a common problem, no matter how angry you are nor how much you rant. With the advent of the internet, and sites like this one, we can rapidly discover how frequently a specific problem occurs. As I have said before, this does not appear to be a widespread problem.

    What this really means to you and others in the same boat (accurately adjusted free play and sufficient experience at using a clutch) is that you were one of the very few victims of a faulty clutch - plain and simple. What that also means to you is that you can feel pretty confident just replacing it with another KTM OEM clutch will solve the problem for the expected life of the clutch, and you can be reasonably assured that lightening won't strike the same place twice. Not guaranteed, but reasonably assured.
    #54
  15. justinope

    justinope Long timer

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    Totally understand that view, my worry is that without a clear indication towards what the defect in the OEM clutch pack was- how is one to know that is the correct solution?

    I'm definitely not trying to rant about it or doomsay even, I am just worried it is more widespread and theres a greater issue to solve. Sorta oddball example, but someone ran a poll on the big FB group (who has had issues / who hasn't) and it came back as 13/228 had some kind of issue so far ~5%
    #55
  16. TrailTrauma

    TrailTrauma Nemophilist

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    I asked my dealer when I took the most unceremonious of deliveries - 'is there anything I need to know?'. The service guy laughed and said 'you probably know more about the bike than we do...'. Nice. Looking back it may have been a good time for a dealer to say some things like - 'hey, if you've never had a cable clutch, here's how to adjust freeplay .. check it regularly. OH, and NEVER feather your clutch in sand with the TC set high!'. Throw away comments like that might spark discussion which could save both client and dealer a few headaches.
    #56
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  17. Thumper Dumper

    Thumper Dumper Been here awhile

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    After reading just about every post on the forum regarding the 790 it appears that most of the USA dealerships carry multiple brands, In South Africa KTM only sells KTM and the staff are pretty knowledgeable although it can differ from one dealership to the next. Having said that I doubt any dealer would give tips on clutch adjustment or use of the clutch and TC unless asked.
    If you ride a bike you should read the manual, it will tell you how to adjust your clutch and seeing as the majority of 790 riders are older than the hills most should be familiar with a cable clutch.
    I also doubt that any dealer was given any specific instructions regarding the frailty of the clutch when feathering it with TC set high (if this is even an issue).
    I don't know if the clutch adjustment is a problem, if there is a manufacturing defect or poor design but I don't think pointing fingers at the dealerships is going to solve any problems.
    #57
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  18. TrailTrauma

    TrailTrauma Nemophilist

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    FIFY :1drink
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  19. Thumper Dumper

    Thumper Dumper Been here awhile

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    :fpalm
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  20. windblown101

    windblown101 Long timer Supporter

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    Well said. On a new model release the vast majority of dealers don't have any more working knowledge of a new model than the buyers buying them. It takes the bike being out in the real world for awhile to develop knowledge of any quirks, traits, or weaknesses and dealers aren't in the business of rider training. It seems reasonable as you mentioned that the issue is either due to design weakness, manufacturing fault, or user error. I don't recall any early reported clutch failures on Tiger 800s or Honda ATs which both use clutch cables and I can't recall a report of burnt clutch plates grenading previous to the 790. While user error or abuse is certainly not off the table (I don't rule that out as the cause of mine being a bit toasty at 12k) it still remains true that most folks buying big ADV bikes are not first time buyers and the affected riders that have been riding for a long period of time are now for the first time experiencing an early failure that their previously learned habits had not caused them. Something is different about this clutch.

    If the clutch by design is more intolerant of being out of adjustment or less than steller technique than average then a bit more care by the riders may be all that is required to prevent any issues. @AdvRonski provided a beautiful example of how well this clutch can hold up under hard riding.

    If it's a manufacturing discrepancy it's possible we may never hear about it and it will mysteriously just stop happening.

    I'll be more conscious of clutch adjustment even though it's not new territory for me. I've had plenty of manual clutch bikes, two in the garage right now with 3 times the miles I have on the 790. I'll also be more conscious of avoiding situations where I might have fanned the clutch in response to TC kicking in which would definitely be user error, though perhaps forgivable for an old luddite? :)
    #60
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