replacement rear master cylinder

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Caley-Thistle
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replacement rear master cylinder

Post by Caley-Thistle »

Hi
Does anyone know of an alternative NEW rear master cylinder that can be fitted or adapted to fit?
CBX1000Z

Thanks

Caley Thistle

jnnngs
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Re: replacement rear master cylinder

Post by jnnngs »

Hi,

I have to ask - why not use an original rear master cylinder? Getting a new one may be hard to find, but they can be refurbished OK.

Paul.

Caley-Thistle
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Re: replacement rear master cylinder

Post by Caley-Thistle »

Thanks Paul, I didn't think about getting the old one refurbished. I'll see about getting it resleeved when I get back from offshore. I am still interested to know of anyone who has managed to fit a non CBX rear master cylinder though.

Cheers

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wyly
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Re: replacement rear master cylinder

Post by wyly »

I bought a master cylinder rebuild kit for the front and back from my local Honda dealer...and a new reservoir for the front to replace the yellowed original. No reason something else won't work but why would you?
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

daves79x
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Re: replacement rear master cylinder

Post by daves79x »

Well, you would if your master cylinder bore was pitted, which many are. I have a whole box-full of pitted front master cylinders. They can be re-sleeved, as was mentioned. Rear master cylinders can get pretty bad as well, and usually leak at bit no matter what due to being mounted upside-down. There are, however, plenty of CBX rear master cylinders out there to be had. F-bike rear master cylinders will work as well, you just have to use the CBX inlet spigot.

Dave

Caley-Thistle
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Re: replacement rear master cylinder

Post by Caley-Thistle »

F-bike...?

Not sure what bike you mean Dave...

Caley Thistle

daves79x
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Re: replacement rear master cylinder

Post by daves79x »

Probably Bol-Dor (sp) bikes to you. CB750F, cb900F, CB1100F over here.

Dave

cbx1956
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Re: replacement rear master cylinder

Post by cbx1956 »

Dave is correct. I'm busy working on my '81 900F Boldor rear master cylinder as I write this- I have just powdercoated it myself with my home kit. It's almost identical to the CBX & also the CB750F of the same era except that the inlet spigot on the CBX is at angle

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swarrans
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Re: replacement rear master cylinder

Post by swarrans »

Sorry to resurrect an old thread (but better than starting a new one?)

It looks like my 82 CBX master cylinder is pitted (looks kind of mottled) - I've tried putting new seals in but it still leaks (although the brake feel was rock solid and it works fine).

Someone posted in another thread that he had found a cheap chinese MC that worked - any ideas? I'm loathe to buy an expensive second hand MC and find it's no better than mine...

Simon

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swarrans
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Re: replacement rear master cylinder

Post by swarrans »

Just in case anyone is interested and has the same problem as me with the rear master cylinder corrosion, the £12 Chinese unit I bought is almost a direct fit and has really got me out of a jam. I will probably paint it to make it blend a bit better but took the photo so you could see it.

It's a remarkably easy fix - just tap the bottom mounting point, drill the top one slightly to line up and shorten the link rod - job done, brake works great and no leaks all for less than half the price of a OEM seal kit! I know purists will hate it but I had little choice.

Image

Simon

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NobleHops
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Re: replacement rear master cylinder

Post by NobleHops »

Got a link?
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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swarrans
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Re: replacement rear master cylinder

Post by swarrans »

Not sure how useful it will be because I'm in the UK Nils, but it'll give you an idea. A lot of them have elongated slots which obviously wouldn't be as good.
https://www.ebay.co.uk/itm/Motorcycle-D ... 2749.l2649

Simon

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NobleHops
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Re: replacement rear master cylinder

Post by NobleHops »

Thank you Simon, much appreciated.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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wyly
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Re: replacement rear master cylinder

Post by wyly »

swarrans wrote:
Thu Feb 25, 2021 8:22 am
Just in case anyone is interested and has the same problem as me with the rear master cylinder corrosion, the £12 Chinese unit I bought is almost a direct fit and has really got me out of a jam. I will probably paint it to make it blend a bit better but took the photo so you could see it.

It's a remarkably easy fix - just tap the bottom mounting point, drill the top one slightly to line up and shorten the link rod - job done, brake works great and no leaks all for less than half the price of a OEM seal kit! I know purists will hate it but I had little choice.

Image

Simon
looks good, I wouldn't even paint it.
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

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