Topic: Master Cylinder Question: Old Style W/Screw-on Cap vs The Later Ones.

[bill440cars]

      Thing is, I've got the 80' CB750K that had a master cylinder like the SOHC4 750 (and various others) on it, instead of the one that was made for it. I want to know, if one is better than the other? I actually like the fact that the older one has only the seals to be concerned about, whereas the later model one has the resevour that can deteriorate as well as the seals. I have one like the one that was meant for it but will need a rebuild kit as well as a new resevoir and I have the type with the screw on cap. Just like to know what others think, as far as which one is better or if either is better. Thanks     

[tbpmusic]

Bill -

Info I've gathered, dealing with these things.

The old screw-cap is probably for a single-disc model, with a piston diameter of 12.7 mm.

Newer ones are for dual disc models, and have a 14mm piston.

Which to use??  Your call. Use of the dual-disc models on a single disc may result in a LOT of force down at the caliper - maybe it will work nicely, though.

bill2

[bill440cars]

        Hey Bill.   This is the one that should be on it (and it's only got a single disc).

         


        And this is what's on it presently.





        May go ahead and use the old style. I just want to make sure it works good enough. Trying to use what I've got, ya know?

                       Thanks for your reply on that,  Bill

[TomC]

hi tbpmusic
     I have small, medium, & large SOHC4s. I have a pile of screw-cap master cylinders. All of them are 14mm bore. Can you or anyone else tell my what the 12.7mm bore master cylinders actually fit?
          TomC in Ohio

Bill -

Info I've gathered, dealing with these things.

The old screw-cap is probably for a single-disc model, with a piston diameter of 12.7 mm.

Newer ones are for dual disc models, and have a 14mm piston.

Which to use??  Your call. Use of the dual-disc models on a single disc may result in a LOT of force down at the caliper - maybe it will work nicely, though.

bill2