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Rear master cylinder not building pressure?
- 78kz1k
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21 Mar 2012 00:50 #510974
by 78kz1k
Rear master cylinder not building pressure? was created by 78kz1k
Hello all,
I have recently bought a 78 KZ1000A2 from a friend of mine. It wasnt running but I figured for 150 bucks I could get it running for cheap. The bike was all there and after some new plugs, she fired up!
I've bought a few things from z1enterprise.com for the carbs and ignition.
One thing i didn't buy was anything for the brakes. Both front and rear calipers were rebuilt. The front works flawlessly. The rear on the other hand has been a pain in the rear. Literally! The rear master cylinder would not build line pressure and the piston in the master was stuck at the top. I rebuilt the master and still didn't work. The piston was slow returning to the bottom of the housing and built zero line pressure. I took the line off the master cylinder and it didn't even push any fluid out of the port.
Any ideas on how to fix. I know they sell a rebuild kit but am nervous that I will run into the same problem. My bore pretty good in the master. Is there any aftermarket/custom mounted master that works? Anything that anyone has tried/done that has worked?
Thanks!
I have recently bought a 78 KZ1000A2 from a friend of mine. It wasnt running but I figured for 150 bucks I could get it running for cheap. The bike was all there and after some new plugs, she fired up!
I've bought a few things from z1enterprise.com for the carbs and ignition.
One thing i didn't buy was anything for the brakes. Both front and rear calipers were rebuilt. The front works flawlessly. The rear on the other hand has been a pain in the rear. Literally! The rear master cylinder would not build line pressure and the piston in the master was stuck at the top. I rebuilt the master and still didn't work. The piston was slow returning to the bottom of the housing and built zero line pressure. I took the line off the master cylinder and it didn't even push any fluid out of the port.
Any ideas on how to fix. I know they sell a rebuild kit but am nervous that I will run into the same problem. My bore pretty good in the master. Is there any aftermarket/custom mounted master that works? Anything that anyone has tried/done that has worked?
Thanks!
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- fivestring
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23 Mar 2012 04:20 #511405
by fivestring
4 out of 3 people have trouble with math
Current
1978 KZ1000A2A, hardtailed, bobbed and stretched
my build thread
1977 Yamaha XS750 (parting out)
1978 Honda CB750 Four
1981 Yamaha XS650
1982 Yamaha XS650
Former
1980 Kawasaki CSR750
1980 Suzuki GS850L
1982 Suzuki GS1100K
1987 Suzuki GSXR1100
1985...
Replied by fivestring on topic Rear master cylinder not building pressure?
I also just acquired the same model and I just got my rear master cylinder working apparently for the first in a very long time, judging from the amount of crud in the system.
Mine wouldn't build pressure at first either. So I took the banjo bolt out of the top and held a finger over the hole and pumped the b rake. It squirted fluid then. It seems the system needs back pressure to work properly.
This was after I had already disassembled the cylinder and cleaned all the components with soap and water then used compressed air to clear all water and be sure the tiny orifices were open.
Mine wouldn't build pressure at first either. So I took the banjo bolt out of the top and held a finger over the hole and pumped the b rake. It squirted fluid then. It seems the system needs back pressure to work properly.
This was after I had already disassembled the cylinder and cleaned all the components with soap and water then used compressed air to clear all water and be sure the tiny orifices were open.
4 out of 3 people have trouble with math
Current
1978 KZ1000A2A, hardtailed, bobbed and stretched
my build thread
1977 Yamaha XS750 (parting out)
1978 Honda CB750 Four
1981 Yamaha XS650
1982 Yamaha XS650
Former
1980 Kawasaki CSR750
1980 Suzuki GS850L
1982 Suzuki GS1100K
1987 Suzuki GSXR1100
1985...
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