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Master Cylinder Repair

Discussion in 'Norton Commando Motorcycles (Classic)' started by NASAman, Jun 13, 2018.

  1. NASAman


    Feb 17, 2018
    I have a 1974 Norton 850. The master cylinder is in dire need of repair. The piton measures .620 inch so i Believe this is the standard 5/8" piston. I have read about replacing this with a 13 mm kit. Can someone recommend a place in the states that can rebuild this for me? is this something normal people can do in their shop or does it take a machine shop? I plan to bead blast all the corrosion and paint off the outside of the cylinder and repaint it. Any recommendations on the paint?[​IMG]
  2. Tornado

    Tornado VIP MEMBER

    Dec 5, 2017
    Look up user Madass on this site...he sells a resleeve kit to take it to 13mm...not hard to perform with his instructions. Seals/piston rebuild kits readily available on-line. Note you might want a new brake light switch as well...mine turned out to be failed but only discovered after got the system all bled and ready....had to repeat the bleed following replacement of switch....might be hard to test switch without having it under oil pressure though.
  3. Guido


    May 23, 2011
    x2 on the Madass kit from Don Pender. I did the rebuild myself. Your MC has been rusting for some time. What you'll need is to get a cylinder hone to clean up the bore prior to install of the insert. I couldn't get the insert to go in so I honed it a little at a time until it was a sliding fit. I thoroughly washed it, glued it in, assembled it, bled it and it was done. The difference in braking was amazing.
    As far as paint, I used "hammer paint".
    I also found stop light switches online for about $10 ea
  4. JimNH


    Jan 4, 2014
    Another possibility is an exchange MC from Clubman Racing. It will have a fresh powder coat and look like new.
    More money though, of course.

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