Size of the Master Cylinder - BMW G310 R/GS Forum
 2Likes
Reply
 
LinkBack Thread Tools
post #1 of 33 (permalink) Old 12-18-2018, 09:48 PM Thread Starter
Senior Member
 
Kris's Avatar
 
Join Date: Dec 2018
Location: India
Posts: 631
Size of the Master Cylinder

does anyone know what is the size of the front master cylinder on gs? it is my experience with many bikes that they come stock with too big MC causing wooden feel in brakes. I changed MC in all my bikes, usually to one number smaller. I believe that the MC in this bike is 12.8mm or even 14mm. there is a way to calculate the MC/calliper-pistons ratio to find the right set up. Smaller MC allows more braking power with less force required. If the MC is far too small however, it will cause the brake lever travel too far.
Kris is online now  
Sponsored Links
Advertisement
 
post #2 of 33 (permalink) Old 12-19-2018, 08:12 AM
Super Moderator
 
Cees Klumper's Avatar
 
Join Date: Mar 2018
Location: Marina del Rey, California
Posts: 308
Garage
Send a message via Skype™ to Cees Klumper
So you are saying most motorcycle and brake manufacturers don't know what they are doing? Seems far-fetched to me. My brakes are perfect.

2018 G 310 R, 2016 C 650 Sport and 1976 (!) Yamaha XS650
Cees Klumper is online now  
post #3 of 33 (permalink) Old 12-19-2018, 08:32 AM Thread Starter
Senior Member
 
Kris's Avatar
 
Join Date: Dec 2018
Location: India
Posts: 631
Quote:
Originally Posted by Cees Klumper View Post
So you are saying most motorcycle and brake manufacturers don't know what they are doing? Seems far-fetched to me. My brakes are perfect.
no, please do not misunderstand me. the bike companies design the brake system for people who are not sensitive enough to brake correctly, so that they do not kill themselves. wooden brakes force one to use a lot of force to brake, but they also are safety precaution against locking the front wheel. when you say that your brakes are perfect, are you referring to gs310g?

'perfect' is a relative term anyway. most people are content with their brakes because they do not know that their brakes can be much better. it is a matter of perspective. many bikers think that if they press their brake lever and the brake lever does not move much, this indicates that the brakes are in optimal condition; but this actually means that their brakes are too hard and lack both modulation and power.

Last edited by Kris; 12-19-2018 at 08:37 AM.
Kris is online now  
post #4 of 33 (permalink) Old 12-19-2018, 09:35 AM
Senior Member
 
Join Date: Oct 2016
Location: Montreal, Qc, Canada
Posts: 134
Kris,

I have found that simply changing the lever to an ajustable one corrected most of the 'Wooden' feel.
Anyway, for my short fingers, the travel was much too far away from the handlebar to get any kind of feeling.

I doubt that BMW was afraid of front wheel lock since they use ABS.
I think it was a cost cutting measure, easily corrected through eBay and Chinese manufacturers of ajustable levers.
bbbelanger is online now  
post #5 of 33 (permalink) Old 12-19-2018, 10:11 AM
Senior Member
 
G0MYW's Avatar
 
Join Date: Sep 2017
Location: Marlow. UK
Posts: 159
Garage
Have you tried changing the brake pads.
Try a Non sintered set it may well give you the feel that you are looking for.
Wemoto offer both 'flavours' by 2 different manufacturers.
G0MYW is online now  
post #6 of 33 (permalink) Old 12-19-2018, 10:23 AM Thread Starter
Senior Member
 
Kris's Avatar
 
Join Date: Dec 2018
Location: India
Posts: 631
Quote:
Originally Posted by bbbelanger View Post
Kris,

I have found that simply changing the lever to an ajustable one corrected most of the 'Wooden' feel.
Anyway, for my short fingers, the travel was much too far away from the handlebar to get any kind of feeling.

I doubt that BMW was afraid of front wheel lock since they use ABS.
I think it was a cost cutting measure, easily corrected through eBay and Chinese manufacturers of ajustable levers.
yes, for sure, adjustable levers are a must. not so much for clutch lever, since you want to open it pretty wide to be able going into the neutral, but for brake side it just a both comfort and safety measure. keeping the brake lever as close to your hand as possible, assuming that the set up is not too soft as for the lever to hit the handlebar, make such a huge difference. luckily, there are many cheap Chinese levers available of very good quality, short or long, which offer such adjustment. however, having this adjustment does not change the general braking feel.

as to the locking the wheel, ABS is the last salvation, which also may fail at times. but the danger of hard, non-gradual braking is that one can lose control over the bike even before the actual lock-up of the front wheel occurs.

I can just share my experience with changing master cylinders. before I had to use three or four fingers to make the bike stop in emergency situation, and now with the smaller MC, one finger is enough and there is much greater modulation. I did that change to Versys 1000, Vulcan S, Tiger 800, CRF 250, and both of my Royal Enfields. If people trust so much manufactures, why the aftermarket companies make so much money? OEM brakes, suspension, seats, and what not, are often produced in lower costs to save money. Well, the bigger vs smaller MC will not make difference in production costs, so it is beyond me (other than the safety measure or the fact that people naively assume that firm lever equals better brakes), why they do that.

the great thing about gs310 is that it is fitted with radial calliper and four pistons. this will no doubt improve its braking capability. sliding two piston callipers are much inferior.
Kris is online now  
post #7 of 33 (permalink) Old 12-19-2018, 10:36 AM Thread Starter
Senior Member
 
Kris's Avatar
 
Join Date: Dec 2018
Location: India
Posts: 631
Quote:
Originally Posted by G0MYW View Post
Have you tried changing the brake pads.
Try a Non sintered set it may well give you the feel that you are looking for.
Wemoto offer both 'flavours' by 2 different manufacturers.
the sintered pads offer more biting but it is only the MC/calliper ratio that change the hydraulic force upon braking that translates into hard/soft feel in braking action. with organic pads you have false sense of softness, because they are just acting more gradually upon the rotor. at the end, you want biting power of the brake pads combined with enough modulation and minimum effort from your hand to stop the bike. the smaller MC the less effort is needed to stop the bike. sport bikes favour bigger master cylinders because they want to have less brake lever travel to save time in racing situation.
Kris is online now  
post #8 of 33 (permalink) Old 12-20-2018, 07:59 AM
Super Moderator
 
Cees Klumper's Avatar
 
Join Date: Mar 2018
Location: Marina del Rey, California
Posts: 308
Garage
Send a message via Skype™ to Cees Klumper
Hi Kris, thanks for that clarification. My 310 is the 'R'. I can compare it to 5 other motorcycles I currently own, and a couple more I used to ride. The R's brakes are really great, although I must add that the previous owner (who drove it only 300 miles before selling it) installed shorty levers.
All my driving is on city streets of Los Angeles, i.e. I use the brakes constantly, and sometimes have to stop very quickly.
G0MYW and Israel Pastelin like this.

2018 G 310 R, 2016 C 650 Sport and 1976 (!) Yamaha XS650
Cees Klumper is online now  
post #9 of 33 (permalink) Old 01-06-2019, 01:26 AM Thread Starter
Senior Member
 
Kris's Avatar
 
Join Date: Dec 2018
Location: India
Posts: 631
Quote:
Originally Posted by Cees Klumper View Post
Hi Kris, thanks for that clarification. My 310 is the 'R'. I can compare it to 5 other motorcycles I currently own, and a couple more I used to ride. The R's brakes are really great, although I must add that the previous owner (who drove it only 300 miles before selling it) installed shorty levers.
All my driving is on city streets of Los Angeles, i.e. I use the brakes constantly, and sometimes have to stop very quickly.
As I posted in another thread, I fitted 11mm master cylinder. Oh, man, what a difference. Before I had to use my both hands to stop the bike in emergency situation. Now, i can stop with one finger. It is ridiculous that they fitted 13mm MC on this bike. It is just not safe! On much bigger bikes with double rotors/callipers they use 14mm and even that is too big. For instance, I changed on my Tiger 800 MC from 14mm to 12.7mm, and now the brakes work as they should.

It is a cheap modification that will transform your braking experience. I am sure, you can get second hand 11mm MC on ebay, and brake lever to match. For instance, you can look for MC for 250KLX kawasaki, or Rebel 300 Honda.

Last edited by Kris; 01-06-2019 at 01:32 AM.
Kris is online now  
post #10 of 33 (permalink) Old 01-06-2019, 09:31 AM
Super Moderator
 
Cees Klumper's Avatar
 
Join Date: Mar 2018
Location: Marina del Rey, California
Posts: 308
Garage
Send a message via Skype™ to Cees Klumper
Sorry Kris, but I have to once again disagree with you: the stock brakes are extremely safe, there is absolutely no need to replace the master cylinder with anything different. I suggest you have your stock brakes examined under warranty by BMW because they may have been defective in your case.

2018 G 310 R, 2016 C 650 Sport and 1976 (!) Yamaha XS650
Cees Klumper is online now  
Reply

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Size of rear wheel nut Old boy Service And Maintenance 18 12-20-2018 08:21 PM
Chain size MichaelJ Engines and Technical Discussion 6 03-31-2018 07:50 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome