790 Reported Clutch failures - My 12k mile examination

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

  1. MN rider

    MN rider Been here awhile Supporter

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  2. TrailTrauma

    TrailTrauma Nemophilist Supporter

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  3. 1coolbanana

    1coolbanana Long timer

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    WOW....thats certainly more price competitive!
    Wonder if the springs are heavier or same?
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  4. TrailTrauma

    TrailTrauma Nemophilist Supporter

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    Yeah, they don't show any specs. Odd.

    Their clutch plates are numbered 6 + we reuse 1 of the OEM plates, so is that more than OEM or add up to the same? Thicker than OEM?
  5. AdvRonski

    AdvRonski They call me......Ronski

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    I got a set of the Barnett clutch springs today, and measured them against the stock springs. The OEM springs are 43mm long, the Barnett springs are 43.7-43.9mm, and are made from a slightly smaller diameter wire, but have fewer coils.
    At 30mm, the OEM springs have a force of 45 lbs. At the same 30mm installed length, the Barnett springs have a force of 50 lbs, about 10% stronger.
    I'm still not having any clutch issues, but I will probably try these out sometime soon.
    IMG_20200427_155037.jpg
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  6. nibby

    nibby Been here awhile Supporter

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    @AdvRonski - Good stuff, update the post please when you start using them.
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  7. Amarok63

    Amarok63 Adventurer

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    Hi,
    Information for larger drilling of the oil nozzle.
    I did not have a problem with the clutch of my 790R but in preventive I made the modification of the oil jet which I drilled at 0.5mm.
    I ordered a spare nozzle 63533001030 and then I checked the oil pressure at the filter cover as recommended in the workshop manual section 24 pages 379-380-381.
    Pressure minimum 1.8 bar and Maxi 4.5bar.
    My motorcycle displays 3500Km counter.
    The 0.3mm nozzle removed had some traces of very fine dirt which could not block it. IMG_20200201_122422M.jpg
    For my motorbike with the 0.3mm nozzle I had a cold 2.14 bar at 20 ° C oil temperature and 10 minutes later while the fan started 1.90 bar and 65 ° C oil temperature, measured on the cover of oil filter with engine at idle speed.
    I then set up the replacement nozzle pierced at 0.4mm, the values were always the same with 1.92bar at 60 ° C.
    I dismantled the nozzle and increased the hole to 0.5mm, the drill I used made a diameter of about 0.55mm.
    Controlling the pressure with this nozzle pierced around 0.55mm also gave 1.90 bar at 65 ° C. IMG_20200413_160056M.jpg
    All these manipulations lasted a full morning to test the different solutions, each time I dismantled the nozzle.
    I do not recommend drilling the nozzle without removing it from the shaft as I have read that some people were wondering.
    It is therefore possible to pierce a nozzle at 0.5mm without risk of loss of oil pressure in the general circuit.
    A nozzle pierced at 0.5mm will give 3 times more oil flow to the clutch discs without reducing the engine oil pressure, which is good to know for those who have this fear.
    I drove about 400Km since the modification before the COVID confinement and the operation of the gearbox and the shift to neutral are exactly the same as before the replacement of the 0.3mm nozzle.

    I made this modification because I quite often use the clutch of the motorcycle on very small mountain roads.

    Attached Files:

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  8. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    Thank you for extremely valuable post!
    @Allucaneat
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  9. new2adv

    new2adv Converting gas into wheelies since 1974

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    Thank you @Amarok63! This is very helpful, especially the oil pressure measurements.
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  10. cjracer

    cjracer AWD please!!

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    Wonderful test setup and useful information. I was planning to setup this test next week as I was also intrigued. Great job!
  11. [Art]

    [Art] Been here awhile

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    Linked from the FAQ for posterity.
  12. gsuks

    gsuks Long timer

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    thanks for the test and information

    I am not a technical person but I do have a query
    would the oil pressure change if the engine was revving at a higher rpm than tick over? for instance 4000 or 5000 or 6000rpm and if so would the bigger hole make a difference then?
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  13. Amarok63

    Amarok63 Adventurer

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    For the tests I did, I did not run the engine higher than 4000 rpm and as far as I can remember the pressure does not go up much.
    It seems to me that it has remained below 3.0 bars. at the pump outlet there is a pressure limiter which is installed to stabilize this pressure in higher speeds.
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  14. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    In any event, the higher the pressure, the lower the percentage of oil will be bled off. Again, your experiment is probably the most useful thing posted here from a longevity of the motor/clutch point of view and I wanted to say thanks again.
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  15. BHoward

    BHoward Been here awhile Supporter

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    Does anyone have a clutch oil jet they would sell me?
    Please PM. Thanks.
  16. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    Is KTM still out? Do yourself a favor and buy the 0.5 from CJ Designs. Drilling out the stock one is not worth the price difference. If you have to have the stock one, I can go back and look up the dealer in PA where I found one when I buggered mine up removing it. He had two left when I ordered mine.
  17. typeamark

    typeamark Been here awhile

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    Second the CJ Design source
  18. Orfeas

    Orfeas Been here awhile

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    2020 790 ADV-R, 2200km - Magura Hymec & Camel clutch arm.
    I had great fun on an enduro trail but the clutch didnt cut it. Asking too much I guess!
    B2DBE78A-FECC-4125-B17F-9CA62FDBA393.JPG IMG_0579.jpg IMG_1110.jpg IMG_1112.jpg

    New clutch pack for reference:
    IMG_1113.jpg
  19. GonFern

    GonFern Adventurer

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    Has anyone heard from KTM on this recently? I just booked my bike for the break in service at 600 miles and my dealer said that KTM now recommends removing the clutch cover and checking the oil Jet. Sounds like even KTM is leaning toward the clogged jet theory. Interesting that they would even care to check since "it's a wear item"
  20. Velociraptor

    Velociraptor TrackBum Super Supporter

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