1974 Handle Bar Master Cylinder.

Discussion in 'Airheads' started by thebisch, Dec 3, 2020.

  1. thebisch

    thebisch Been here awhile

    Joined:
    Nov 7, 2013
    Oddometer:
    312
    Ok, here's the deal.

    I have ridden mostly Harley's, so my experience with "real" brakes is about zero. With that said I have never really had a problem with my Harley brakes. I am not an aggressive rider.

    For a point of reference my experience with the original '74 BMW set up is as follows...

    Leaking under tank MC (unknown to me at the time, out of site, out of mind, the main motivation to change to the handle bar setup), old fluid that had turned brown, good (IMO) lever feel, action, and range of motion. Have ridden the bike around the neighborhood for an hour or so up to probably 30 or 35 MPH. Like I said, brake action seemed fine/good to me. Brakes didn't really stop the bike all that well.

    Today I was able to do an hour or so around the neighborhood with the new MC. Brake feel much improved! Lever feel doesn't feel much different than the feel of my '05 single disk Sportster with aftermarket braided line and new fluid. Braking? OMG! What a difference! Seat of the pants, stops probably similar to the '05 Sportster.

    I know, not the greatest test just blasting around the neighborhood, but it's something.

    This was with the old pads from around '79 and the original '74 solid disc which has a couple of pretty deep grooves in it. I can only imagine the next step up improvement with new pads and EBC rotor.

    In retrospect, a definite do again, NO QUESTION, especially considering how much the rebuild kit and parts are for the UTMC, and the chance there will still be problems.

    Oh, and for my hands, the tilted down switch gear isn't a problem at all. That was my main trepidation originally.

    The @bmwrench brake line is perfect and the pricing was very reasonable! Highly recommended.

    The new brake light switch clicks like a Japanese bike. I kind of dig that! LOL.

    Added bonus! My clutch interlock switch disintegrated into pieces. As everyone may know, on a '74 this switch is the same as the brake light switch on the /5 and '74. This is a $50 switch! I was going to just permanently jumper the wires for the interlock. Well, now that I have the new brake switch on the new MC/lever, my good brake light switch has been transplanted to the clutch interlock. In my pea brain, if I was planning to buy a new switch, this project just saved me $50! LOL.
    #21
  2. thebisch

    thebisch Been here awhile

    Joined:
    Nov 7, 2013
    Oddometer:
    312
    Why would you want to lock up the wheel?
    #22
  3. sizzlingbadger

    sizzlingbadger Boxer Fan

    Joined:
    Jan 28, 2013
    Oddometer:
    700
    Location:
    New Zealand
    I wouldn't normally, but if the brakes are capable of "just" locking the wheel then I know they are no longer the weakest link in the physics involved in stopping.
    #23
  4. bmwrench

    bmwrench Long timer Supporter

    Joined:
    Nov 10, 2006
    Oddometer:
    9,164
    The standard single disc really "wasn't much". Before I converted my fake R100RS to dual discs, I could stop fairly quickly, but I had a forearm like Popeye's.
    #24
    sizzlingbadger and Jim K in PA like this.
  5. Brun

    Brun Been here awhile

    Joined:
    Jun 29, 2012
    Oddometer:
    870
    Location:
    BorderBurg, South East Oz.
    Well done, @thebisch. I'm glad the mod worked for you.

    You'll be loving that brake even more when you get to ride some twisties.
    #25
  6. thebisch

    thebisch Been here awhile

    Joined:
    Nov 7, 2013
    Oddometer:
    312
    I'm looking forward to it. Hopefully by next season if all goes as planned.
    #26
  7. thebisch

    thebisch Been here awhile

    Joined:
    Nov 7, 2013
    Oddometer:
    312
    It was WAY cheaper to do the handlebar MC than convert to drums (which I did consider!)!
    #27