Relocate brake master cylinder?

[PureXaos]

Has anyone tried/failed/succeeded to relocate the front brake master cylinder? I've been looking around and haven't really found anything.

I'm thinking if I fabricate a bracket to seat it between the forks I'd have to make a lever operated by a cable. I'm aware it might not be possible depending on how much force can be transferred/cable

 

[figure8]

I've seen it done. Relocated under the tank and operated as you said, with a cable.

 

[PureXaos]

I've seen it done. Relocated under the tank and operated as you said, with a cable.

Thanks man!

 

[DoubleE]

Google "BMW remote master cylinder" to get you started. Like Figure8 said, these are hidden under the tank.

 

[azman857]

I heard It wasn't the same "solid" feel as direct control...I did not experience this first hand...

 

[DoubleE]

Azman, I have the same understanding. Cables stretch and are sloppy; hydraulics are much more instantaneous. I love the look of my bike, but hate that wart on the right side of the handlebars. I think that slop/delay of 2 to 3 feet of cable and a remote m/c may be mitigated by either a dual disk on the front, or a superior brake i.e. Brembo. I would like to know if anyone has tried this concoction?

 

[retiredgentleman]

Its a bad idea. You will lose "feel", which means you lose the fine control of the braking power. Could be quite dangerous, especially when it first starts to rain.

 

[PureXaos]

Ok. Well, crazy, harder idea here. How much brake fluid do you need in your reservoir? Im guessing the stock is around 3 to 4 ounces? If you could safely function with 1.5 to 2 ounces perhaps a reservoir hidden inside the handle bar would be feasible; extensive modification required but feasible.

 

[wannabridin]

What you need is a radial master cylinder, or at least a more modern axial MC. Then you can run a short piece of tygon for your reservoir, such that it never goes dry. Then you can be much cleaner up on the bars and have modern performance.

 

[PureXaos]

What you need is a radial master cylinder, or at least a more modern axial MC. Then you can run a short piece of tygon for your reservoir, such that it never goes dry. Then you can be much cleaner up on the bars and have modern performance.

Wow awesome man thanks!!

 

[Paul Sutton]

With Rototiller bars I found the Yamaha XV250 (XV535) master cylinder is much smaller than the stock version so does not dominate the handlebars. The reservoir is very compact and all metal with a small round sight glass for checking the fluid level.


View from riders position.

 

[Paul Sutton]

Forgot to say, with master cylinders the reservoir is usually set above the piston so that gravity keeps the piston primed. If you fit a reservoir remote to the master cylinder and below the level of the piston inlet you run the risk of getting air into the brake lines.

 

[PureXaos]

So something like this. That would be good.

 

[Paul Sutton]

That Brembo still needs to have a reservoir connected to it. The reservoir may, or may not, look like a wart because there is a huge range of reservoirs available through Ebay with various dimensions/wart-factor e.g. very nice machined Aluminum reservoirs in different colors. From the Brembo website we have the following:

"The RCS radial master cylinder is available in two different versions: 19 and 15. The numbers indicate the diameter of the piston and define the respective applications for the two versions: the 19RCS must be used in a dual disc system with 4-piston non-floating calipers, whereas the 15 RCS may be installed in single or dual disc systems with 4-piston floating calipers."

These master cylinder piston dimensions are larger than the stock XS master cylinder piston (for a single front caliper with one piston). When used on an XS they will make braking difficult with the stock single front caliper setup. Several people have used Brembos on the XS but in combination with a Brembo caliper which has more than one piston. For good braking it is important to have the correct ratio of master cylinder surface area to the total slave cylinder surface area. Hence the Brembo statement above specifying the caliper to be used in conjunction.

Think about what you would like to do with the braking system and then ask for some more opinions to ensure you do not sacrifice braking performance for cosmetic looks. Perhaps you want to go Brembo master cylinder + Brembo caliper. If so then there are other issues to address such as rotor size. But there are several people on this forum who have used Brembos and know the ins and outs. I have never used Brembo.

- Paul.

 

[PureXaos]

Thanks a lot Paul. That explains the the missing Link for me as far as the relationship. Scooters never had hydraulic anything! So a lot more for me learn.

 

[Paul Sutton]

If you look on Ebay you will see loads of cheap master cylinders. I would never again buy one because they are cheap. On another forum a retailer stated that the failure rate was approximately 4 out of 5 when he sold them. I bought one and it was impossible to remove the screws to fill the reservoir but I did manage to get a refund. The reason I said to look is because you will see how small the all metal reservoirs are compared to the stock XS. They are the same size as those on the Yamaha XV250 and many other bikes from the mid 80s on. The XV250 is only suited to the original XS Specials with handlebars that look a bit like a Rototiller. However you will find good quality Nissin (OEM manufacturer) master cylinders for straighter bars selling secondhand, but again you need to know what size piston the MC needs to have. For example: My 81 XS SH had a 14mm Nissin MC with a single disc and single floating piston caliper. The braking was not very good so I bought a secondhand Nissin 12mm MC for £20 and this improved the braking. It also got rid of that large stock reservoir.

If you post details of your bike model/Year and a photo of the front caliper/rotor and the MC then others will be able to advise you on the alternative MCs you could fit. I assume you have the original Nissin MC on your bike so check the underside where it has Nissin cast in and next to this will be the piston size. Typically you will see 14 for 14mm or 1/2 for half inch (12.7mm). This will help.

Have fun!.

 

[PureXaos]

Thanks Paul. Yeah I have never purchased party from eBay except in the case that it was an original piece off something.