Master cylinder swap

  • Kitten Tooth
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Master cylinder swap

11 Mar 2012 04:04
#508989
I have a front master cylinder that is in great shape from a 1976 KZ400D3. It came off of a single disk brake setup. My 1981 KZ1000LTD is dual disk in the front and i would like to swap out the master cylinder from the KZ400 to my KZ1000 because it looks cool as hell (circular with a cap that unscrews). The way i see it, i could just unscrew the line that goes into that junction on the lower triple tree on the KZ1000, pull that master cylinder off, install the one from the KZ400, bleed the brakes, and be on my way. All it is is an inlet and an outlet inside the master cylinder. If the fluid is topped off and theres no bubbles or gunk in the lines, it would work on a dual disk setup wont it? Any help would rock.


Thanks guys,
KT
1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH

DO A BARREL ROLL!!

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  • 750steve
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Re: Master cylinder swap

11 Mar 2012 07:54
#508999
As the 400 master cylinder is for single & the 1000 is for a dual setup i dont think the cylinder for the 400 will push enough fluid. You'll end up with the lever going to the bars at worst or a 'soft' lever at best.

Grab another lever thats used to running a twin disc setup, don't take chances with brakes.
07 ZX6R Race Bike
1977 Z750 B2 Twin
1976 Z650 B1

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  • Kitten Tooth
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Re: Master cylinder swap

12 Mar 2012 00:56
#509166
even if the fluid is topped off and all is as it should be? All it is is smaller. If theres no air in the lines and its got fluid, you'd think it would have just as much pressure as the other one but using less fluid in the reservoir.
1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH

DO A BARREL ROLL!!

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  • Kitten Tooth
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Re: Master cylinder swap

12 Mar 2012 01:00
#509167
well if anyone else says no.... ill probably still try it :D and let you know what happens.
1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH

DO A BARREL ROLL!!

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  • ramtough_63
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Re: Master cylinder swap

12 Mar 2012 01:15
#509168
it will probablly be fine while I am sure there are numbers somewhere on pressure, volume, etc...That say otherwise

but i am pretty sure the only difference is the splitter in a dual set up alot of people just add a dual banjo bolt
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  • DaddyJama
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Re: Master cylinder swap

12 Mar 2012 01:23
#509172
Think of circles.. Like push pops

Hydraulics work with a relation ship of distance and area..

U push a small area a great distance on one end..(hand movement distance and small master cylinder push pop piston)

The fluid takes that movement and can push a bigger area a small distance on the other(brake piston)

u can ask the small area piston (hand) to move a greater distance to push the bigger area of the multiple calipers.. But if u get the analogy u will see u may pull into the bars by the time u move the brake calipers enough..

This is all theory in that the smaller cylinder may have some extra in it.. Depends on what the brains were thinking when they designed it..

If they were designed to be a perfect fit, it prob won't work..

Id eBay a newer master cylinder designed for a modern sport bike.. New bikes use 7/8th bars as well
2005 636 - track bike
1982 kz440ltd - new toy;)

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  • The Milkman
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Re: Master cylinder swap

12 Mar 2012 10:03
#509191
No eBay APP ID and/or Cert ID defined in Kunena configurationI put one of these:
on my dual caliper 650 and it works fine. Looks good too.
Les
78 650-C2, Stock engine, Jardine 4-2 Exh., 17-38 sprockets, dyna ignition and coils, coil wiring mod, carb mod.
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  • z1kzonly
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Re: Master cylinder swap

12 Mar 2012 11:25
#509199
Yes it will work in physics. But it will be spongy, and the lever will pull all the way to
the handle bar.
That is why all the Z1 and H2 guys want the coveted 5/8" bore master cylinder fo
the dual disk conversion.
I am assuming you have this early Z1 KZ900 style master cly.
I am working on some here.
How is this for a story:
I finally bug a family member to bore these out. I tell him to 5/8"!
Stock bore is 14mm.
So he being the professional machinist that he is, he feels that it should something
under american size 5/8"! being of metric, japanese style. So he thaught he was correct and told me so.
So me being a nice guy said thanks alot! Wow you did me a favor.
So now I have 3 bores that need to be bored another .005 -.010" I will probally finish bore
them with some 220 wetsand paper.
Livin in "CheektaVegas, NY
Went thru 25 of these in 40 yrs.
I SOLD OUT! THE KAW BARN IS EMPTY.
More room for The Old Girl, Harley 75 FLH Electra Glide,
Old faithful! Points ign. Bendix Orig. carb.
Starts everytime!

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  • roy-b-boy-b
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Re: Master cylinder swap

12 Mar 2012 11:44
#509201
Think of it as redneck antilock brakes. You will not be the first to do this. Roy
1979 LTD Street Fighter.1977 KZ1000

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  • steell
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Re: Master cylinder swap

12 Mar 2012 12:22
#509203
roy-b-boy-b wrote: Think of it as redneck antilock brakes. You will not be the first to do this. Roy

Short, sweet, and to the point :laugh:
KD9JUR

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  • M357.5
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Re: Master cylinder swap

12 Mar 2012 12:37
#509205
roy-b-boy-b wrote: Think of it as redneck antilock brakes. You will not be the first to do this. Roy

Yep, been there myself when I swapped dual disks onto my KZ750B1, didnt have a proper master cylinder and its a good job my rear brake worked very well cuz the fronts were USELESS till I swapped on a proper master for duals.
83 KZ750L X2 + goodies = Project
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  • Kitten Tooth
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Re: Master cylinder swap

14 Mar 2012 00:25
#509519
well ok you guys, i guess like 7 people say it aint gonna work right so i wont do it That was my next idea though. A newer circular style master cylinder off of a crotch rocket of some sort. I love the redneck anti lock breaks. Just like the rust holes in my pickup are redneck air conditioning :D i appreciate the heads up you guys.
1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH

DO A BARREL ROLL!!

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