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Discussion Starter · #1 ·
Hi all,
I have a 98 Zx9r and the front brakes are disconcerting in how far the lever travels before finding good power. Pads and fluid have been changed, and I also hear it’s a common complaint. The bike shop suggests a newer slave cylinder off a zx10 for example is the fix.
If anyone has done this or has any suggestions, please let me know
Thanks people
Ash
 

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You will read of all kinds of upgrades to fix brake problems and I’m not here to tell you not to.
In my experience (ZX7R- same brakes), these brake require regular maintenance to keep them working to their potential. I change my fluid every two years, caliper seals every 4-5 and rebuild the master every 4-5. If you neglect servicing these calipers, you end up with corroded pistons and then it gets pricey. To rebuild the master takes about 1 hour and less than $50 in parts so very worth it.
 

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Discussion Starter · #3 ·
You will read of all kinds of upgrades to fix brake problems and I’m not here to tell you not to.
In my experience (ZX7R- same brakes), these brake require regular maintenance to keep them working to their potential. I change my fluid every two years, caliper seals every 4-5 and rebuild the master every 4-5. If you neglect servicing these calipers, you end up with corroded pistons and then it gets pricey. To rebuild the master takes about 1 hour and less than $50 in parts so very worth it.
Thanks Ninjanut :)
 

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Also did new lines ,ebc pads and had to buy new ebc rotors because they where warped. 15 thousand out of round. The bike stops almost as good as my ducati 1299
 

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Discussion Starter · #7 ·
Well, I have installed a master cylinder from a ZX10 , rebuilt the calipers, new fluid and pads, but it’s not much better. Shop is suggesting a rebuild of the zx9 master ... I’m a bit lost??
 

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I mentioned above that I am in the minority with my belief that the 6-piston Tokico brakes are good brakes for the street if properly maintained.
Last fall I noticed that my lever would pull into the bars. My plan was to totally go through the brakes. I split the calipers and replaced all the seals and o-rings. Rebuilt the master cylinder ($35 OEM part) and replaced the cup on the resevoir ($20 OEM part). Replaced fluid and bled the system.
Now my lever only pulls in about 10-15mm and is hard as a rock.
Since you’ve done the seals, were the pistons in good condition? Did you buy a used master? If so, it may have required rebuild as well. Did you replace the cup on the resevoir? This is often overlooked as overkill but there is a reason Kawasaki sets out a brake system maintenance.
 

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Discussion Starter · #9 ·
Thanks @ninjanut, I really appreciate your advice. Maybe the zx10 master needed a rebuild as you suggest.... so I will have the original rebuilt and see how we go. The pistons were in good shape apparently. I will look at the reservoir as well. I’ll let you know how I go...cheers Ash
 

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I've found over the years most competent spanner Monkeys that don't repair Bikes for a living have no issue rebuilding the Braking system it's Bleeding that seems to stump them.
Not saying this is the case just an observation over many years ;)
It can be a pain getting them last Bubbles of Air out.
After major Brake work I always Pump the Lever quite sharp and fast and hold it on, Attach a Cable Tie (Zip Tie) to the Lever back to the Bar and snick it up to apply moderate pressure to the system and leave it like that for a good 12 Hrs.
It more often than not reduces the Lever travel and also serves to check for Fluid Leaks.
 

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Discussion Starter · #11 ·
I've found over the years most competent spanner Monkeys that don't repair Bikes for a living have no issue rebuilding the Braking system it's Bleeding that seems to stump them.
Not saying this is the case just an observation over many years ;)
It can be a pain getting them last Bubbles of Air out.
After major Brake work I always Pump the Lever quite sharp and fast and hold it on, Attach a Cable Tie (Zip Tie) to the Lever back to the Bar and snick it up to apply moderate pressure to the system and leave it like that for a good 12 Hrs.
It more often than not reduces the Lever travel and also serves to check for Fluid Leaks.
Novel approach , thanks KevA. I really appreciate your advice. Cheers Ash
 

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Novel approach , thanks KevA. I really appreciate your advice. Cheers Ash
I went through the drama of putting a Nissin radial master cylinder onto my C2. It was from a Triumph Daytona, which I believe is the same as what you'd find on GSXR's and maybe some Kawasakis. I had also rebuilt the calipers and put on some HEL braided lines (two lines to the MC) along with the radial MC converter. Oh, and some new Braking Wave discs and Braking pads. I found that the lever would hit the instruments when turned to the right, applying the brakes for you. The radial MC sticks out that much further and I couldn't find any levers which would give the clearance required. Anyway, the lever travel from all that was a little bit more than what you'd expect but they seemed to have a good amount of power - it's a 3/4" bore (19mm) so has a fair amount of leverage (to the detriment of feel).

I gave up on the radial MC a couple of weeks ago and stuck the original MC on. Unbolted the whole lever assembly and dropped it through the behind the headlight so I could get away with not emptying the fluid out of the system. Unbolted the MC and converter and stuck the old MC on. The MC was dry as I had rebuilt it. Put it all back on the handlebars and start bleeding. I hadn't primed anything so the MC was full of air. Pinched that hose between the cup and MC a few times and get a few bubbles back up, do that a few more times, give the lever a few pumps, squeeze that reservoir hose a few more times, pump brakes, give the lines and MC a few light taps with the handle of a screwdriver to jiggle the air back up.... Left it overnight and did the same the next day and it didn't take long at all to get proper lever pressure/travel. Amazing. Three weeks of it sitting in my garage and it's still good. I haven't ridden the bike yet to test the brakes, to judge any drop in power from going back from the radial MC to axial MC.

That said, the Nissin MC I got and found it didn't fit still bugs me. Did you use an earlier ZX10 MC, where the MC bore is on an angle? In that it's not 90 degrees like a normal radial MC?
 

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Discussion Starter · #13 ·
@rod750
I went through the drama of putting a Nissin radial master cylinder onto my C2. It was from a Triumph Daytona, which I believe is the same as what you'd find on GSXR's and maybe some Kawasakis. I had also rebuilt the calipers and put on some HEL braided lines (two lines to the MC) along with the radial MC converter. Oh, and some new Braking Wave discs and Braking pads. I found that the lever would hit the instruments when turned to the right, applying the brakes for you. The radial MC sticks out that much further and I couldn't find any levers which would give the clearance required. Anyway, the lever travel from all that was a little bit more than what you'd expect but they seemed to have a good amount of power - it's a 3/4" bore (19mm) so has a fair amount of leverage (to the detriment of feel).

I gave up on the radial MC a couple of weeks ago and stuck the original MC on. Unbolted the whole lever assembly and dropped it through the behind the headlight so I could get away with not emptying the fluid out of the system. Unbolted the MC and converter and stuck the old MC on. The MC was dry as I had rebuilt it. Put it all back on the handlebars and start bleeding. I hadn't primed anything so the MC was full of air. Pinched that hose between the cup and MC a few times and get a few bubbles back up, do that a few more times, give the lever a few pumps, squeeze that reservoir hose a few more times, pump brakes, give the lines and MC a few light taps with the handle of a screwdriver to jiggle the air back up.... Left it overnight and did the same the next day and it didn't take long at all to get proper lever pressure/travel. Amazing. Three weeks of it sitting in my garage and it's still good. I haven't ridden the bike yet to test the brakes, to judge any drop in power from going back from the radial MC to axial MC.

That said, the Nissin MC I got and found it didn't fit still bugs me. Did you use an earlier ZX10 MC, where the MC bore is on an angle? In that it's not 90 degrees like a normal radial MC?
thanks for your thoughts rod750 - it’s been a process of elimination. Finally we have a reasonable result . The MC was off a 2010 zx10, a radial one which like yours worked better, but totally interferes with the steering as it was hitting the dash and clearly was the wrong fit. So I have had the original MC rebuilt, along with the calipers and I think some braided lines will be next, but at least I have some pressure and feel better then it was.
 

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Have you been able to get the brakes bled nicely? Mine were shits of things to get the fluid through the calipers, but then again I was doing all that with them fitted to the bike.... If I'd have hung them up they probably would have just about bled themselves.

I also swapped the clutch perch for one from a ZX10 as that gigantic one which comes standard on the ZX9 looks awful. The ZX10 unit has that spring controlled slack adjuster too, which is easier to work with than the lock ring.
 

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You don't need new parts or parts from another model. You have an air or pressure loss problem in the system. The travel is directly proportional to whether there is air in the system and whether your master cylinder (you said "slave" which is for the clutch) and calipers need to be rebuilt. Moisture gets into brake fluid regardless of what you think is happening, because brake fluid is an alcohol based material and it is by nature hygroscopic (it attracts water). Over time the moisture damages internal parts of all vehicle brake systems. And NEVER put silicone fluid in your brake system. Without going into detail it has to do with the physical properties of that type of fluid, it can cause your brakes to seize and you will crash. You can buy all the parts to rebuild the master cylinder(and your calipers) and do it yourself if you have a inner and outer circlip snap ring plier kit. After you rebuild the master, you should dissassemble the front calipers completely, including removing the pistons and hydraulic rings, clean the metal interior surfaces very, very carefully, with no metal touching inside the caliper (use plastic or wood to pry anything that needs some help), put the pistons and caliper halves in a bucket of hot water with TSP + dish washing liquid and a small amount of citrus degreaser, rinse several times with hot water, blow out all the channels, clean the grooves for the pressure rubber rings and the dirt skirt, clean the pad holding hardware, reassemble (don't lose the small o-ring that goes between the halves) after all is completely dry, make sure the pistons are lubricated with Dot 4 fluid before placing them in the cylinders, then you have to bleed from each caliper and possibly from a third location (you have to add a Banjo joint with a bleed valve to do that) until no air is in your system. And make sure you tighten the caliper fasteners to factory specifications for torque. I suggest you buy a Vacula or equivalent product to bleed your system. Air and fluid getting by the rubber pressure rings is the main reason you get excess lever travel, it is not a "common problem" of the bike, that is baloney. No bike is engineered to have excess lever travel. Your bike should have a solid feel to the brake lever and the rear brake pedal and it should stop quickly. If not, refer to above instructions.
 
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Discussion Starter · #16 ·
You don't need new parts or parts from another model. You have an air or pressure loss problem in the system. The travel is directly proportional to whether there is air in the system and whether your master cylinder (you said "slave" which is for the clutch) and calipers need to be rebuilt. Moisture gets into brake fluid regardless of what you think is happening, because brake fluid is an alcohol based material and it is by nature hygroscopic (it attracts water). Over time the moisture damages internal parts of all vehicle brake systems. And NEVER put silicone fluid in your brake system. Without going into detail it has to do with the physical properties of that type of fluid, it can cause your brakes to seize and you will crash. You can buy all the parts to rebuild the master cylinder(and your calipers) and do it yourself if you have a inner and outer circlip snap ring plier kit. After you rebuild the master, you should dissassemble the front calipers completely, including removing the pistons and hydraulic rings, clean the metal interior surfaces very, very carefully, with no metal touching inside the caliper (use plastic or wood to pry anything that needs some help), put the pistons and caliper halves in a bucket of hot water with TSP + dish washing liquid and a small amount of citrus degreaser, rinse several times with hot water, blow out all the channels, clean the grooves for the pressure rubber rings and the dirt skirt, clean the pad holding hardware, reassemble (don't lose the small o-ring that goes between the halves) after all is completely dry, make sure the pistons are lubricated with Dot 4 fluid before placing them in the cylinders, then you have to bleed from each caliper and possibly from a third location (you have to add a Banjo joint with a bleed valve to do that) until no air is in your system. And make sure you tighten the caliper fasteners to factory specifications for torque. I suggest you buy a Vacula or equivalent product to bleed your system. Air and fluid getting by the rubber pressure rings is the main reason you get excess lever travel, it is not a "common problem" of the bike, that is baloney. No bike is engineered to have excess lever travel. Your bike should have a solid feel to the brake lever and the rear brake pedal and it should stop quickly. If not, refer to above instructions.
Thanks so much for your thoughts and taking the time to write this - much appreciated!
 
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