Ktm freeride brake upgrade

Discussion in 'Electric Motorcycles' started by lauris47, Oct 19, 2019.

  1. lauris47

    lauris47 Adventurer

    Joined:
    Jun 20, 2016
    Oddometer:
    81
    Location:
    Denmark
    Hey, as many complains about KTM freeride brakes I do too.
    (valid for ktm 85, 250, 350? E-xc and whatever else is using these "bicycle" brakes)

    I have ktm E-XC freeride with Formula brakes.
    I bought 4 new metal pistons as the originals in the brake are from plastic.

    After I changed those, I felt only slight increase in braking - they were more sharp.

    After few days of driving, brakes overheated and stopped working.

    I noticed that the brake fluid had some white crystal particles - I released that when I bled the brakes two fluids shouldn't have been mixed. Originally there should have been Dot 4 and I added Dot 5.1 which according to charts are mixable. So good lesson, always drain the old fluid, as you don't know if previous owner did things according to the manual.

    I ordered new master piston for Formula brakes to replace old rubber washer (40€...) as I suspect that went bad from over pressure.
    (I suspect that crystal particles jammed fluid return chamber, fluid got trapped in the line, hence brakes overpreasured and overheated)

    I also ordered two sets of brake master levers. As I plan to do that upgrade as well.

    I realized that all common brakes are using m10 Banjo bolt and lines, while Formula brakes use m8. Simplest option would be to get some sort of reducer that when fit to the brake master accepts standard Formula m8 bolt. And that's where I am stuck. I spend 4 hours looking for such adapter, without luck.

    If anyone knows where to get such bolt, please let me know. Any other options and suggestions are also appreciated.

    Attached Files:

    #1
  2. lauris47

    lauris47 Adventurer

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    Update I manage to fix the brake. I replaced master piston, but at the time it seemed that it did not solve the issue.
    Then I did combination of two things, drilled secondary holes into banjo bolts and replaced rubber washers to copper.
    This made my brakes work again!

    However they are still crap, so I will replace the master cylinders when I get them. I decided to modify original brake lines by attaching regular 10mm banjo ends as I cannot find simple adapter, that could convert m10 to m8 banjo bolt.
    #2
  3. lauris47

    lauris47 Adventurer

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    Update: I would not recommend making a new line from the original, as it is probably not the same in thickness so a standard banjo attachments doesn't seal well. Mine was leaking no matter the attachment technique I tried.

    Then I bought and tried two sets of master cylinders. First were Brembo RCS 19 copies, seemed very interesting, but they were so strong that the line blew at the attachment at the testing. I fited second master cylinder, with smaller piston and a new standart line with 10 mm Banjo bolt. I used 10mm Banjo at the top and 8mm Formula Banjo at the bottom. Worked crappy as the original. I drove with this setup for a few weeks, until I got fed up again.

    Finally I bought a master cylinder from KTM SMC R (Brembo). I haven't tested it much but I am feeling that It didn't help either, brakes are just dangerously weak as they were before.... I cannot even lock the wheel, what about doing a stoppie...

    So, I changed the whole system except the brake calliper. Although I changed the pistons to steel as the originals were plastic as mentioned before. I think that changing the whole brake calliper is the hardest part as probably not many if any can be fitted. The attachments on original are radial-style but with very narrow space in between.


    At this point I'm out of options. I'll updated if I come up with something new.
    #3
  4. lauris47

    lauris47 Adventurer

    Joined:
    Jun 20, 2016
    Oddometer:
    81
    Location:
    Denmark
    DSC_5083.JPG
    DSC_5160.JPG DSC_5159.JPG

    Attached Files:

    #4
  5. lauris47

    lauris47 Adventurer

    Joined:
    Jun 20, 2016
    Oddometer:
    81
    Location:
    Denmark
    Hi again, anyone knows ktm 690 front brake calliper dimensions? I'm thinking of buying and attaching that to e-xc feeride.
    #5