Front brake master cylinder

[wjbarber]

I've an old front master cylinder off a single disc 1980 SG in need of repair. The reservoir looks in a bad way apart from all the other insides and generally speaking the rest of it is bad too. I've looked on ebay and there are no decent looking used ones out there. I don't want to spend the £100-150 for a new one, as i see the prices for XS used or new stuff is pretty high compared to other makes.

Does anybody know somewhere you can buy the new plastics and other parts for it? Or is it possible to use a different make like off a Suzuki or other Yam model that works exactly the same and similar spec? I'm just finding everything over-priced for what i'm getting. I hope someones had some success regards this issue, its doing my head in

Cheers
Will

 

[Fleksta]

You can use any brake master you want, so long as it accepts the 10mm banjo and has a proper bore diameter. IIRC the bore diameter should be 14mm for a single disc brake.

 

[fredintoon]

I've an old front master cylinder off a single disc 1980 SG in need of repair. - - - Does anybody know somewhere you can buy the new plastics and other parts for it? Or is it possible to use a different make like off a Suzuki or other Yam model that works exactly the same and similar spec? - - -

Hi Will,
rebuild kits & some different master cylinders From Heiden Tuning:-
http://www.heidentuning.com/p/36/3539/mo74-cgp2|20=1
It's amazing how a lick of paint will fix up the caliper's outsides, reservoir and all.
That and replacement innards should fix it right up.
Note that the original '77 & up single disk caliper on North American XS650s has a piston diameter that's too effin' big to work nice with a single caliper although it works perfect with twin calipers.
Best you check what m/c piston your set up needs before paying out to fix up the wrong thing.

 

[fredintoon]

Hi again Will,
best you send nh-jk a PM if you want his m/c.
His post in the want ads asks for a PM response because he won't get notified otherwise.

 

[wjbarber]

Been a while but i'm back with a related issue.

The stock systems all seem to have the tilted reservoirs and seeing as i'm going with flat bars, they wont do. So i thought how about something new and modern... What about a YBR 125 replacement?? They go with the 7/8 bar and are suitable for a single disc (1/2" bore). Has anyone else tried one of these? Trouble is i can't tell whether they use a 10mm banjo. They're cheap and there's LOADS of em on ebay!

Any thoughts on this matter will be very welcome!

 

[fredintoon]

Been a while but i'm back with a related issue.

The stock systems all seem to have the tilted reservoirs and seeing as i'm going with flat bars, they wont do. So i thought how about something new and modern... What about a YBR 125 replacement?? They go with the 7/8 bar and are suitable for a single disc (1/2" bore). Has anyone else tried one of these? Trouble is i can't tell whether they use a 10mm banjo. They're cheap and there's LOADS of em on ebay!

Any thoughts on this matter will be very welcome!

Hi Will,
FYI, my slanty-reservoir m/c has been working OK on straighter bars ever since I swapped out the bike's stock rototiller bars back in 1987.
Tilt the bars hard left to put the m/c more towards level when you take the top off.
Mind you, the stocker is too big for a single caliper.
I fixed that by going dual-disk but a 1/2" bore m/c on a single disk will be OK too.
Buy the YBR m/c anyway.
You should also be swapping to a stainless brake hose so if the YBR m/c has a different banjo, buy the brake hose that fits it.

 

[wjbarber]

Cheers mate! Feeling better about going the YBR route now.

Just wondering thought, say if the banjo is bigger on the master cylinder side and i'm still the 10mm banjo size at the caliper end, will i be in trouble then or do i need to change the caliper too?

Will.

 

[weekendrider]

Have a line made with the correct sizes on each end.
The m/c's from the standard/roadster models are flat not angled/sloped.
Like Fred I've used a "specials" angled m/c on flat bars with no problems.