Master cylinder rebuild

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Clarkie_10
On the street
Posts: 13
Joined: Sat Apr 11, 2015 6:52 am
Country: England
Suzuki 2-Strokes: GT550 ( 1975 )

Master cylinder rebuild

Post by Clarkie_10 »

Hi Guys ,
I decided to powder coat my front brake caliper and master cylinder over the winter . ( GT550 m )

I ordered what I thought was the correct parts , however when they arrived they did'nt match what I had taken out !!

I was then advised that some kind person had replaced my master cylinder with a GT250 unit .
can someone please advise if I have the parts in the correct order to be fitted as I cannot find any info on line .

First in is spring open end , black rubber clips into small end of spring , then small thins brass disc , followed by ali piston c/w rubber seal , then all held in place by a circlip then fit rubber boot ???

Thank you

( damned photos won't upload ! :(
Craig380
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Re: Master cylinder rebuild

Post by Craig380 »

Have a look here at the exploded diagram of the master cylinder:

http://www.oldjapanesebikes.com/mraxl_G ... /index.php" onclick="window.open(this.href);return false;
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: Master cylinder rebuild

Post by sportston »

would that mean you have an incorrectly sized master cylinder? I know many GT550s had twin discs, while the GT250s had single disc.
I am not sure of the bore sizes, but it would make sense that on a bike with two calipers you would have a different size master cylinder than a bike with one caliper. You might wish to check this with one of the more "model specific" experts on here.
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Alan H
Moto GP
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Suzuki 2-Strokes: 4 x GT550s - J, M, A, B.
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Re: Master cylinder rebuild

Post by Alan H »

GT550s never had twin discs as standard. People used to fit them by using a 750 left fork leg, caliper and m/c until the later models with 'twin disc' fork legs.
GT750 master cylinders had a 'D' underneath, for 'dual' and was a larger diameter piston.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
sportston
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Joined: Wed Jul 10, 2013 12:04 pm
Country: England, UK
Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: Master cylinder rebuild

Post by sportston »

Alan H wrote:GT550s never had twin discs as standard. People used to fit them by using a 750 left fork leg, caliper and m/c until the later models with 'twin disc' fork legs.
GT750 master cylinders had a 'D' underneath, for 'dual' and was a larger diameter piston.
I stand corrected. Thanks for setting me straight.
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