Topic: interchangeability of CB master cylinders

[ltrr1971]

My question is does all the CB four cylinder bikes, 350f,550f,750f up to 1976 use the same master cylinder and it's internal parts?  I thought that they were all the same but am not sure.  I have a 76 750f, 76 550f, and a 73 350f and would like to rebuild all three masters starting with the master from the 76 750f and then putting it on the 350f while I do one of the others.  I picked the 750f master as first as the bike is waiting to rebuilt and the 350f is running but needs a master cylinder rebuild.  Also, which brand and where to get the rebuild kit?  thanks!

[d_soles]

Well, let me put it this way.

My 1973 CB500 parts bike has the old metal, cylindrical shape MC with a twist on cap.

My 1975 CB550F has a nasty little plastic-box looking MC, with 4 screws holding the cover on. 

But, I'm going to downgrade to the better looking old style.  The plastic box on the 550 is disgustingly disintegrated.

Doug

[ltrr1971]

The ones I'm referring to have the cylindrical shape with the twist on cap.

[razor02097]

I have the one with the plastic body.  When I got the rebuild kit it came with a new cup, cap, screws and O ring along with the internals for the master cylinder.

[Jerry Rxman Griffin aka MuthaF'er]

ltrr,

I'm assuming you are using one of the online microfiches to cross reference parts between bikes?!

ie http://www.motogrid.com/pages/parts/viewbybrand/7/default.aspx

Order the rebuild kits from Honda! I prefer ServiceHonda.com due to their discount and excellent service. They have another website address for ordering too but I do not have it tagged.

[bryanj]

Only the GL1000 and the 77/78 750F have different cylindersand whoever has the square bodied mast on the 55F it aint original

[d_soles]

Wouldn't surprise me, I've found a lot of....fun.... on my bike from the PO...where is the square bodied MC off of, then?

Doug

[cycleman]

What matters is if the bike is a single disc or dual disc.  The piston size in the master cylinder is different.  Usually a 16 mm or bigger for dual discs & 14 mm for single discs. Match the master cylinder to your brake system.

Other than that its just cosmetics.  Whatever suits your fancy.

[Laminar]

Wouldn't surprise me, I've found a lot of....fun.... on my bike from the PO...where is the square bodied MC off of, then?

Doug

It could just be a generic master cylinder, but the '80s Hondas all came with square master cylinders that should be a direct swap as long as you're getting one from a bike with the same brake setup (single/dual calipers).

[bryanj]

May not even be Honda, probably just what he had lying about or available in breakers