Master cylinder rebuild

[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]

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;

[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.

[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.

[sportston]

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.