Results 1 to 5 of 5

Thread: Need help with '88 K75C master cylinder

  1. #1
    Registered User rall275's Avatar
    Join Date
    Apr 2017
    Harrisburg, IL

    Need help with '88 K75C master cylinder

    [SIZE=3]Well, I'm taking the Master Cylinder apart because it looks like it's leaked in the past and I want to change the o ring and reservoir, lube the throttle components under there, and check the condition of the piston and rubber. I'll probably also repaint the around there that's been damaged by the leaking brake fluid.

    I've removed what I could except the screw that holds the switch on and this mythical 3mm set screw I can't find. I read Drake Smith's "Repair a Leaky Master Cylinder," but the photo almost shows a metal reservoir and may be different than my bike.

    Do I need to remove the combination switch's screw?

    How do I access the phillips head screw holding the reservoir from below with such little clearance?

    Where is this 3mm set screw?

    The photos I'm sending:

    reservoir that has a screw that is difficult to reach. I'm replacing this part

    Drake Smith's photo of the set screw location. Can't orient it in my mind and unsure if matches mine

    frontal view of my progress so far on breaking down the M/C

    top view showing encrusted brake fluid and gunk

    Thanks guys!
    Attached Images Attached Images

  2. #2
    Registered User
    Join Date
    Dec 2008
    Belle Plaine, MN
    Looks like you may need to remove the master cylinder from the handle bar in order to access the reservoir retaining screw from the bottom.

    I'll try to take a look at mine (85 K100RT) to see if there is room for a small bent screwdriver to fit.

    Otherwise, I'm sure someone with more experience will be along shortly.



  3. #3
    3 Red Bricks
    Join Date
    Jan 2007
    Pleasanton, Ca.

    Ignore everything you've read from Drakes post. That is from a different bike.

    To do anything with your master cylinder, you must remove the master cylinder.

    To remove your master:

    Remove the screw that holds the switch plate in place. Then slide the switch plate down 1/8" to disengage the tap that is at the top of the switch plate. Remove switch plate.


    Remove throttle gear cover (large Phillips screw between master and throttle grip). Gently pry up to lift cover straight up.

    Remove two allen head bolts that hold master cylinder to lever perch. slide master cylinder away from perch. Disconnect throttle cable from chain on throttle gear. You can now easily access the screw that holds the reservuoir to the master cylinder.


    When reinstalling the throttle tube, make sure to align the line on the throttle gear with the line on the throttle tube to insure proper operation.


    Whoever lubed these throttle gears went WAY overboard with the grease!

    I would strongly recommmend that you purchase a Clymers manual if you plan on continueing to work on your own bike.


    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  4. #4
    Registered User rall275's Avatar
    Join Date
    Apr 2017
    Harrisburg, IL
    Thanks Lee!

    I'll give your instructions a go. I have a Clymer I use regularly, but their instructions on this procedure were very unclear, like their photos!

    Thanks again. I'll keep you all posted on my progress.


  5. #5


    Hey i think for your 88 K75C issue you should refer some technician like man ....

Similar Threads

  1. 78 100/7 master cylinder help
    By 79woodsie in forum Airheads
    Replies: 4
    Last Post: 10-03-2016, 12:09 AM
  2. ATE Master Cylinder
    By jbarneshb in forum Airheads
    Replies: 4
    Last Post: 12-10-2012, 03:05 AM
  3. Front Brake Master Cylinder Leaking, 89 K75C
    By DEANCOX in forum Flying Brick K-bikes
    Replies: 7
    Last Post: 05-05-2012, 07:47 PM
  4. Master cylinder help!?!
    By spaken71 in forum Airheads
    Replies: 13
    Last Post: 03-02-2010, 07:00 AM
  5. master cylinder
    By ISAMEMON in forum Airheads
    Replies: 5
    Last Post: 11-05-2006, 09:12 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts