1974 Z1 900 Drum to Disk.

OldSchoolKaw86

Active Member
One of the biggest things i have done on my kawasaki z1 900 cafe project was convert the wire wheels to mag wheels, now i have dual disk's up front and a single disk in the rear. I am running calipers off of a 1986 Kawasaki GPZ 900 up front and the stock kz 1000 caliper in the rear. I plan on running a front master cylinder off of a gsxr 1000 for more stopping up front. What would be the best rear master cylinder to use, one off of a gsxr 1000? Or would anyone work? Thanks guy's.
 
i rode my dad's Z1 with the dual disks and gsxr 1000 master cylinder up front and if you have the guts to lock the front brake it will lock it up and stop on a dime. He has a stock kz 1000 or 1100 rear master cylinder, and it just doesn't seem like it grabs all that well......it could just be that he only rides the bike a few times a year if he's lucky. I would think the gsxr 1000 rear master cylinder would stop me like it's not even funny.
 
revheadgl said:
By going larger you will increase brake line pressure. ie; less pedal effort

Other way round - the smaller the master cylinder, the less force is needed for given pressure.

Best regards
Sven
 
scm said:
Other way round - the smaller the master cylinder, the less force is needed for given pressure.

Best regards
Sven


Is that so. Then why do larger systems require a larger master cylinder? I personally dont feel that the master cylinder has a lot to do with the power of the braking system. There are better ones that improve feel at the lever and better modulation. most of your gains would be made in the caliper and pad and rotor. I personally dont use the rear brakes to stop only to trail brake really. Everytime I have had to panic stop the rear brake locks up on me. With all that said I would not go with a smaller master cylinder than original for the system. I would look to make improvements through a stainless brake line and better caliper.
 
thompsonmx100 said:
Is that so.
Yep. Simple physics: pressure equals force divided by area.
Hence the smaller the area...

Then why do larger systems require a larger master cylinder?
Well just to keep the mastrer:slave ratio in a practical range...

revheadgl said:
Good pads are a must and as you stated stainless lines improve brake feel.
Absolutely.
What I had in mind is that old japanese bikes in general have way too big master cylinders.
When people try to improve these systems with some steel braided hose, the effect is often
a glass hard feel at the lever (very little travel needed) with still high forces necessary.
This can be cured with a smaller master cylinder.

I perfectly agree on what you both said about rear brakes.

Best regards
Sven
 
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