Topic: master cylinder replacement...

[jjc6df]

I would like to replace the master cylinder on my 74 cb350f.  I am much more concerned with functionality than originality...any suggestions...?  Thanks again...

[sadams1954]

Why do you need to replace the master cylinder? Rebuild kits are availiable on ebay. If you still need one, I have an original master cylinder and rebuild kit. If you don't feel comfortable rebuilding it, I can do it.

[Jugghead]

Hey guys ... I have had trouble rebuilding my master sylinder.  I have a good condition reservoir that i just put a NOs  rebuild kit in.  I know i assembled it correctly but it still leak fluid past the piston out towards the brake lever.  some annoying drips have landed on my tank and caused small spots of tank discoloration
Any advice as to what i should do to remedy this? thanks. I have a 9.72 350F you can see it in the gallery at the bottom of my post

[sadams1954]

Did you check inside the bore for scratches or corrosion? I used a small round fine wire brush in a twisting to clean out the bore before putting in the new piston. You can usually find a used master cylinder on Ebay but it may be in worse shape than yours. I have an extra one but I would advise rebuilding that one first.

[cmorgan47]

i've been debating rebuilding/replacing with something modern and relocatable.

just put cafe bars on and now, when the forks are straight, the cylindar is at about a 30degree angle.  it's leaking from where the lever contacts the "button" (i know it's not a button, but can't think of a better word)

anybody else had problems with this?
what did you do?
will a rebuild get it done, or is the angle going to cause it to leak regardless?

[sparty]

i've been debating rebuilding/replacing with something modern and relocatable.

just put cafe bars on and now, when the forks are straight, the cylindar is at about a 30degree angle.  it's leaking from where the lever contacts the "button" (i know it's not a button, but can't think of a better word)

anybody else had problems with this?
what did you do?
will a rebuild get it done, or is the angle going to cause it to leak regardless?

I have the same problem at the moment a leak at the lever seal.  I bought a new Nissin MCfrom eBay, bolts and banjos and a Russel braided 9" line.  The new MC should actually be better.  I am rebuilding the entire brake assembly for better feel and power.  I figure that my life is worth a $100.

Sparty

[cmorgan47]

I figure that my life is worth a $100.

yeah, that too.  i was just thinking that i couldn't paint it till i sorted this out.
plus i'm tired of wiping brake fluid on my jeans at every light.

[cmorgan47]

sparty, will any of the brake assemblies (lever and MC) work so long as it fits the bars? 
do i need to worry about piston size?
what else to look for?

[Jugghead]

Did you check inside the bore for scratches or corrosion? I used a small round fine wire brush in a twisting to clean out the bore before putting in the new piston. You can usually find a used master cylinder on Ebay but it may be in worse shape than yours. I have an extra one but I would advise rebuilding that one first.

Hey Steve,
Yup I made sure that all was well inside that baby, and she was smooth as a whistle.  The PO had a rag around it and told me to rebuild it and it would be fine.  I cleaned inspected and rebuilt with a NOS OEM honda kit.  After a few days, it began to weep a bit.  I disassembled it, cleaned it out again, and reassembled the whole thing all over again.  worked OK, but now I have the leak again. GRRR I have another MC but it has a huge gouge inside the bore.  The current one is still black on the outside and smooth on the inside.
What gives?  I do, however, get a good hard brake feel.

[cben750f0]

i used one off a vtr 1000... here are a couple of pics...

peace

[sparty]

sparty, will any of the brake assemblies (lever and MC) work so long as it fits the bars? 
do i need to worry about piston size?
what else to look for?

Look for a Nissin MC from a sport bike.  They work.  The Nissins they are putting on Honda/Suzuki/Kawi are all the same and use the same banjo bolts and banjo adapters. 10mm.

Sparty