Master cylinder

Captmandel

Captmandel

XS650 Addict
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Hey everybody! I have been reading around and it seems like no one ever answers any questions about interchanging master cylinders. I have an xs2 which uses a 16mm bore. The question I have and probably lots of others is can you only use a 16mm bore or can you use 13mm? From what I have gathered, the smaller the number the harder it pulls? Maybe thats wrong.So how small is too small? And what else needs to be changed if you swap master cylinders? So If anyone can please shed some light on this.


tl:dr
Can you interchange master cylinders?
What are the differences?
If you do change, what else needs to be changed?


Thanks!, Josh. :thumbsup:
 
This points me in the right direction but how do I know how big my caliper is? Stock xs2. And once I do know and figure it out how do I know the ratio? What do all those numbers mean? Is there a formula I'm missing? I have a stock xs2 and want to switch to a 13mm MC will that work? Or will it throw me off the bike?
 
With your level of mechanical expertise, it might be wise to leave something as important as the brakes alone :doh:
 
Or something like a forum full of people with more knowledge than me to give me guidance.

I know how to measure things but figured that if anyone one this forum ever switched from a 16mm master cylinder to a 13mm master cylinder they would be able to tell me how it worked for them.

Also I haven't seen a thread like this one posted anywhere so now in the future if anyone has this question they can find help here.

There's only one way to learn this stuff and it's to do it. I may not know a lot now but that's why you will find I have posted a lot of questions to this forum in the last few months.

I appreciate you trying to help me out but if you don't know the answer to a question please don't answer it.
 
By the way this isn't me looking for performance it's that my stock MC is totally ruined and inoperable so I need to get a new one. There's lots of used ones and that's why I'm wondering about the switch. Currently I have no front brakes
 
There are quite a few threads on it actually, I read up on them a month or so ago and decided on an 11mm master cylinder. The base idea I got from it is that, the smaller the piston in the master cylinder, the 'touchier' the brakes are - so you are correct.

XSLeo and gggGary explain it well in here:
http://www.xs650.com/forum/showthread.php?t=11635&highlight=11mm+master+cylinder

I haven't truly give my new master cylinder a good go yet as my build is still going on, but I tested it and like how it feels.. I don't think you'll be thrown over your bars, you'll get used to it.
 
Thank you! Yea I think I'm going to go with 13mm jus because that's what I can get for cheap. Thanks for answering my question and the link. I searched the forum for "master cylinder" and can't find that thread you linked me too. It's pretty informative so thanks again.
 
Captmandel
Sorry you took my answer the way you did :shrug: yes I do know the answer, I think my thread Fazer Blue Spot caliper in the "tech section" shows that.
http://www.xs650.com/forum/showthread.php?t=197
Brakes are serious things, get it wrong & you could be seriously hurt.
From your answer to my link, it seemed to me that perhaps you did not have the knowledge to be working on your brakes. The last thing I wanted to do was give someone some information that encouraged them to work on something they were not equipped to work on & possibly get hurt because of it.
I agree with you that the best way to learn is to get on & do it, with advice from places like this. But perhaps the braking system isn't the place to start.
Good luck with your project :thumbsup:
 
Measure the diameter of your pistons, you have two, go to the chart that 650 Central thoughtfully provides. Decide what is a proper master cylinder to use with a FULLY OVERHAULED caliper and brand new brake lines.
The XS2 was Yamaha's first motorcycle disk brake. There are some issues with the rotor carrier bearing and the "unique" rotor to wheel damping system used for only one year.
That big old 16mm MC has a lot of hydraulic capacity, reduce the amount of fluid moved by going to a smaller MC and poorly maintained components may leave you with a brake lever against the handle bar when you least want it.
So yes you can get better "feel" from a smaller ID MC but it requires a complete system that is functioning optimally. Let us know what you decide and how it works for you?

Part of the reason there is little out there on early brake mods is that if you are serious about brakes, a change to the better front end components found on newer bikes is often the plan of action.
 
KevC I'm not sweating it. I appreciate your knowledge and concern for a newbie.

gggGary I plan on new brake lines, probably steel braided, and rebuilding the caliper. New pads and the 13mm MC. I think I read about a mod to connect the lines to the caliper with out that steel line at the end?

Right now I only have rear brakes so brand new everything is pretty much the only option. The caliper and disc are the only things staying.

Is rebuilding a good option or is buying a newer caliper from mikesxs a better bet?
 
The master cylinder is pretty beat. You may be right but I'd rather just get something new.

I have nothing against going to a pro. I just wanted to see if the forum could help me to know exactly what I need to order before I go spend full retail through a mechanic.
 
On the caliper I think it will depend on the pistons, if they rusted/pitted probably replace makes sense. I just redid an early MC, it went well but parts are hard (impossible?) to find for them.
 

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