Aftermarket Master Cylinder Q/A

[TheCafeKid]

So I snagged an aftermarket front master off of Griffin, one he picked up new on the Bay and then liked a different one better, so he passed his other on to me. I installed stainless lines, all the way on the front brakes and anti dive. I have bled the system untill im getting NO air bubbles, but the lever still feels like total crap. Its nearly to the bar before the brakes really start to slow the bike down. Seems kinda not cool. I can only assume, since the system is bled, that the bore and stroke are simply not right for what the GS brakes require to be most effective... I dunno the bore or stroke off the top of my head, but im looking for an aftermarket job that is as CLOSE TO OEM as possible. Anyone have any suggestions?

 

[Billy Ricks]

So I snagged an aftermarket front master off of Griffin, one he picked up new on the Bay and then liked a different one better, so he passed his other on to me. I installed stainless lines, all the way on the front brakes and anti dive. I have bled the system untill im getting NO air bubbles, but the lever still feels like total crap. Its nearly to the bar before the brakes really start to slow the bike down. Seems kinda not cool. I can only assume, since the system is bled, that the bore and stroke are simply not right for what the GS brakes require to be most effective... I dunno the bore or stroke off the top of my head, but im looking for an aftermarket job that is as CLOSE TO OEM as possible. Anyone have any suggestions?

I'm using a GSXR m/c on my bike. Works great with the 4 pot calipers so it should easily handle your needs.

 

[Dave8338]

Yeah, if you are sure that the system is air free, than your master may be too small for the GS calipers.

The link below will calculate the area of the original master vs that of the new one. The only additional math required is multiply the area by the length of stroke.

http://www.calculateme.com/cArea/AreaOfCircle.htm

 

[Nessism]

The GS brake system is designed to use a 5/8" master cylinder. The single disc bikes use a 14mm master, which is what that popular ebay master measures if its the one I'm thinking of.

 

[Guest]

Did you bleed the M/C?

 

[tkent02]

What condition are the calipers in?
They can do this if they are sticking.