790 Adventure R rear shock failure

Discussion in 'Parallel World (790/890)' started by [Art], Oct 19, 2019.

  1. [Art]

    [Art] Been here awhile

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    Starting a new thread for this. I've read about shock failure since this summer, but it's hard to get numbers. Some theories have been put forward, some products created, but I'm not convinced it's due to the catalyser.

    Can you post if your bike has been affected? Is there more than a few of you?

    I started an entry in the FAQ, but frankly, I need more hard data. Help me improve it.
    #1
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  2. Salzig

    Salzig Long timer

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    If it's due to the catalizer we should also see the standard version fail, but I can't recall any.

    Anyway thank you for all your effort.
    KTM should pay you... or hire a killer :lol3
    #2
  3. Bturner26x

    Bturner26x n00b

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    that’s funny.

    From what I’ve gathered so far, it seems to be an underlying issue w/ the shock itself. I thought the heat theory was a good one at 1st, but after some more digging, I think it’s some kind of a defect. Hopefully you get the data you need to come up w/ the correct answer & KTM will fix the issue. Thanks for all of your the 790 faq work!
    #3
  4. Alpha 1

    Alpha 1 Adventurer

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    maybe you should change it to issues from the factory thread, it would be interesting to see.
    mine is in the shop now for the rear shock @ just over 600 miles, this is its second warranty visit the first at 400 miles counter shaft seal and sending unit for the fuel level were both replaced.
    #4
  5. [Art]

    [Art] Been here awhile

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    No, the other issues are well known at this point. The shock story has been making the rounds lately, and I'd like to get to the bottom of it.

    So, what happened to your shock? just started to leak? More details than that? What have you done these 600 miles? Road? trails? Jumping steps?
    #5
  6. Knolff

    Knolff Adventurer

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    My R has the leaking rear shock. Bike has around 2100 miles on it and I weight about 225lbs. First noticed it when I was trying to locate a terrible burning smell coming from the bike, turns out if was shock oil dripping onto the HOT cat.
    I don't "jump" the bike but I'm sure I've had the rear wheel off the ground a few inches when clearing a water bar or the like. The bike has been ridden approx 60-dirt/40-street (nothing crazy, mostly BDR type stuff). I'll be taking it to the dealer next week to see what they propose. I'll keep you posted
    #6
  7. TrailTrauma

    TrailTrauma Nemophilist

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    If you've been perusing the Suspension Mods thread, then you may have already noted @Konflict Motorsports observations. I can't think of a better source of utterly informed feedback on the 790's shock failings.
    #7
  8. Alpha 1

    Alpha 1 Adventurer

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    did about 170 miles on it the day it started leaking 50% of that was on good gravel roads by good I mean something you could get a any car down, 40% 2 track, only about 10% I would call hard ,nothing the average person on a dirt bike couldn't do. there was a section of the baddest washboard I think I have ever been on - the bike handled it well.
    no jumping not saying its never had both wheels off the ground but nothing really, I've only felt the bottom of the suspension once hit a wash out at speed the forks took the hit not the rear schock. I did not notice the leak the day of the ride when out the next morning to go again and there was a puddle under the shock.
    I'm 250 lbs 6'1" 51 years old. I did just install racks and bags but had nothing in them.
    #8
  9. TrailTrauma

    TrailTrauma Nemophilist

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    What weight springs and coil did you upgrade to? If not, do you have suspension upgrades in the works?
    #9
  10. ShaftEd

    ShaftEd Long timer

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    My rear R shock blew at 2500 miles. Easy dirt and mostly street running. No jumping. Shock seal leaking enough to get on cat and cause smoking. I’m 6’1” and 220lbs. Shock was rebuilt by WP. I’ve now got 3600 miles and have ridden the bike much harder and it’s holding up so far.
    #10
  11. ADVweekend

    ADVweekend Robbie Supporter

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    Same answer as @Knolff for me. Failed at about 2300 after a BDR-esque day, burped it’s oil out and is being worked on by Konflict (aka sitting in a pile of R shocks at their shop while he does R&D to find a lasting solution).

    My R also had its front brakes fail and has spent the past month at the dealer while they troubleshoot. Warranties are great, but geeeeez, they (KTM) solve problems as slow as humanly possible when it’s their money... been a month and they’re finally trying their first fix (rebuild master brake cylinder). Glad it isn’t peak season, I’d be pacing a ditch in front of the shop— the 790’s amazing, love it to death, but I’ve felt the first model year blues and from what I’ve heard I’m in good company :bluduh:cry:bluduh
    #11
  12. windblown101

    windblown101 Long timer Supporter

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    Yep, I went into my purchase of a first model year unit with eyes wide open so the fact that there are some issues isn't a shock. Crap happens. As long as KTM stands behind it and gets things sorted I'm cool with it. They will figure it all out and get it sorted, just don't know how quickly... Redesigning parts, testing, and then getting them into production takes some time.

    My rear shock burped out oil at around 2400 miles. My dealer replaced some o-rings and serviced the shock. It was fine for another 9000 miles. Recently started leaking again though. Bike is in the shop now for a warranty claim. My plan is to stick with the stock shock and see how it all plays out moving forward. If there is no proven long term fix before I'm ready for another long trip I may look at upgrading the rear to something else before I leave, maybe the Xplor Pro. Such is life when on the bleeding edge. ;)
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  13. Some_Dude

    Some_Dude Been here awhile

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    To offer a counter point of data, I’m 193 lbs and at 9000km with no shock issues. Rode moderate offroad, whooped out sand trails, jumped it a handful of times (nothing crazy).

    Last weekend my front fork seals were leaking. Cleaned them with a fork seal doctor and no issues since. I mention this because I’ve ridden in enough sand to compromise the front seals yet the rear seal is holding up.
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  14. TrailTrauma

    TrailTrauma Nemophilist

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    Swiped these images off an open facebook page so folks can see what to expect (visually) when their shock is leaking...

    [​IMG]
    [​IMG]
    Photos credited to: Mark Verschelden
    #14
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  15. tshansen

    tshansen Been here awhile

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    It does not has too look like this, i had a leakage in my front suspension on a bmw r1200 GSA and it was nearly invisible. just luck i saw it when i was cleaning the bike. So i think its a good ide to keep a close eye on this for everyone. I see CAMEL ADV sells a heat shild now? can the heat be the problem for this? hmmm
    #15
  16. Noyah

    Noyah poser

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    From the first post:
    There is a theory going around incriminating the catalytic converter: it is really hot, and very close to the shock, so it is possible that it is heating up the oil or the seals, thus causing the failure. Some facts however don’t align very well with this theory:

    • This failure is only on the R, the S model is not affected at all. If the catalysts were in fact “boiling the oil inside the shock” as I’ve read it in place, there would have been failures of the S shocks as well;
    • There is at least one example of a failing shock absorber on a bike with the catalyser removed from day one. Ergo, the catalyser in that case was not to blame;
    • As bikes get more mileage, failure rate should have increased. This is not the case, the bikes with failing shock absorbers are all low mileage (less than 2k, very new).
    This seems to indicate that the issue is probably not the catalyser but more likely a default on some shocks with a problem from the factory.
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  17. Alpha 1

    Alpha 1 Adventurer

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    no
    no upgrades at this point was planning on getting more time on the bike before I changed anything or made a decision on what if anything to change on the bikes suspension.
    #17
  18. TrailTrauma

    TrailTrauma Nemophilist

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    I think guys like us well beyond the max recommended weight for the OEM suspension, it's likely the best gift this winter could bring. I tried...I raised the front tubes 4mm, and completely maxed out the preload on the rear. Tried a more comfort oriented compression dampening, and increased rebound, but couldn't get it plush enough, no how. So new springs all around for next season. Pop into the suspension mods thread. Lots of good reads there, and solid mentors.

    Initially with the heavier adv bike I didn't think I'd have to upgrade my springs a few weights higher, but I was wrong. It's a shame I didn't do it out of the gate this season.
    #18
  19. Torque

    Torque Been here awhile

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    Guess a list of possibilities and what can be done might be in order. No solid info just throwing them out there.
    I will be purchasing the bike soon and will go right into the suspension.

    1. Heat
    Heat is bad. Reason for the failures? Contributor? I will take these steps. Either remove the cat or get a heat shield. Likely will fabricate a bladder to reduce reservoir piston friction, in addition to carrying a little bit more oil. Everything I can do to keep the shock cool as this promotes more consistency, longer lasting fluid, less wear. Remember a bladder needs service more often than a piston reservoir. So KTM chose a little 46mm shock that runs hotter. Also a few years ago WP chose to change from an aluminum reservoir piston to a plastic one. Seen those fail in the early model 500exc with again the small 46mm shock. The failures were racers and that means heat.

    2. Lubricity
    Type of fluid makes a big difference. I believe it is a balancing act between lubricity keeping the seal slippery on the shaft and viscosity index being the heat range the oil will handle. I have seen seals fail in short order and repeatedly due to an oil company not using enough lubricity. I will be changing the fluid and adding a touch of lubricity additive that will not effect the viscosity index. Keeping in mind a cooler shock may not need the 400 degree oil.

    Heard side load mentioned.
    3. Side load
    Why would this shock have more side movement than any other shock. Thinking out loud here. Piston tolerances maybe allowing more movement between the bushing in the seal head and the piston? Shorter stroke shock? hmm how would that effect the shock. Seems it would be less side load. Maybe one of the engineers on here can contribute.

    4. Faulty seal.
    It is seldom a shock seal blows until it has many more miles than a fork seal. Considering the area the seal lip is covering on a 48mm set of forks compared to an 18mm shock shaft it makes sense. Yes forks get a more direct dirt bath but the shaft size makes a big difference too. I sometimes will switch a seal to another brand that has a bit more squeeze upon insertion into the seal head if they are having a seal failure issue. After polishing the shaft of course and assuring nothing is actually cutting the seal. Also replacing the Teflon coated seal head bushing.
    On another note, We did try a name brand green shock seal head on a pro bike shock once. After about two races the top out rubber / seal disintegrated on a 50mm shock.

    5. Low nitrogen level
    So if the nitrogen level was low the aluminum cylinder / seal head that holds the seals and bushing at the top of the shock would not be held in place by the nitrogen pressure. This would allow it to slide up and down inside the shock body and can wear out several parts in the process. If you lose oil and ride the bike, this will happen as well. So you have a seal head that can wear out the inside wall of the shock body. See that pretty often. Additional side load, yes. Bushing wear, yes shock shaft wear. Heat, aluminum shavings, catastrophic. Wonder why this shock has such a high nitrogen psi as stock?

    Have to get to work but I am sure there are other theory's. Lets here them. One other item. Trophy trucks are building giant diameter shocks. Why? Heat! They can trash their fluid in one whoop section.
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  20. kubcat

    kubcat Been here awhile Supporter

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    What I heard about increased side load is that the angle of the shock between the swingarm and the chassis is much shallower than other bikes that use the Xplor suspension. Although it wouldn't be a lateral side load, I think this shallower angle would increase side load on the bushings, where any load other than in line with the rod would exert sideways forces. But maybe I am describing an "out of line" force that suspension engineers have a different word for.
    #20