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Discussion Starter #21
Yes. If i push the rear caliper pistons back and then pump just the brake pedal, the rear wheel drags again. The brake pedal moves free in the pivot. No effort at all.
 

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Discussion Starter #22
I have also taken the rear caliper out and cleaned everything. It wasnt that bad inside and the piston can be pushed in by hand. Im sure a stuck piston is not the problem.
 

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OK so with that clear then the only reason for the piston not releasing has to be somewhere between the caliper and the fluid reservoir ...... so hoses, master cylinder and reservoir. Something is slightly blocked.

Having made that statement, I assume that the caliper slides on its slider - across the disc not the slider on the swing arm which I have never seen stuck.
 

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Discussion Starter #24
UPDATE...again:crap:

Before i took pieces appart, i pushed the rear caliper pistons fully in. Then installed the pads. Then pressed the brake pedal, the center piston moved first, but when it touched the pads, the outer pistons came off too. The brake was stuck.

Took the pressure differencial valve appart, the one near the rear brake fluid reservoir. Nothing to see here. Everything looked good. Installed it again.

Took the rear master cylinder appart. Couldnt believe it...full of brown mud. This mud came from the rear fluid reservoir down to hose and in to the master cylinder. Stripped the master cylinder. Cleaned everything with brake cleaner. Put everything back on again. Used a professional brake bleeder, and...VOILÁ...

NO MORE DRAG.:D

But...:hmm::hmm:...since my bird is a complete joke, i noticed that when i was triyng to bleed the brakes, no oil was coming from the outer rear bleeder...the one faced to the back of the bike. I can even take it off into my hand and nothing...no oil out of the caliper. The bleeder looks fine, no crap inside, even if i press the brake pedal hard without the bleeder on...still no oil.

Brakes are operating correctly but i can notice there is still some air inside that i cant get it out trough the outer bleeder.

Help please.
 

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Nearly there!
If you look at the schematic that gigby posted earlier in the thread the two outer pistons are operated by the SMC so are effectively operated by the front lever not the pedal which is why you are not seeing any fluid coming out.

Now you have got rid of all the brown mess I would be tempted to run round the bike bleeding everything in the order given in the Factory manual just to make sure there are no air pockets ....... and then zip tie the front lever and pedal on overnight, any last bubbles should be expelled.

Well done keeping on with this!
 

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Ditto what exxelent said. Strip the entire system, clean, flush and freshen up the entire brake system. There is no half job with CBS. Do it properly the first time, service every two years and it will be sweet for a very long time. No de-link needed. Unless you really want to de-link.
Hi eduardo, there is no half job when sorting out the CBS if it has been neglected for a long time. You'll be chasing your tail for days. People are critical of the CBS but there is nothing wrong with it and it operates very well. It's a great system and is very effective on the road. But it is very sensitive to neglect. There will be crud and shit through the ENTIRE SYSTEM and if you do half a job, all you will do is move the crud from one part of the system to another if the job isn't done correctly and in full. You've cleaned one part of the system but the risk is that (may not be the case but we don't know for sure) you may have transfered the crud from one part of the system into the part you have cleaned. And around in circles we go. Study the diagrams provided in this thread, think about fluid transfer and follow the manual when bleeding. To assist bleeding, try to get hold of a air compressor vacuum bleeder or at least a hand operated vacuum bleeder. Bleeding the CBS by the hold pump pump hold method can work but will take forever to get right. Once it's sorted, it'll be easy to service every two years. Cheers
 

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Hi eduardo, there is no half job when sorting out the CBS if it has been neglected for a long time. You'll be chasing your tail for days. People are critical of the CBS but there is nothing wrong with it and it operates very well. It's a great system and is very effective on the road. But it is very sensitive to neglect. There will be crud and shit through the ENTIRE SYSTEM and if you do half a job, all you will do is move the crud from one part of the system to another if the job isn't done correctly and in full. You've cleaned one part of the system but the risk is that (may not be the case but we don't know for sure) you may have transfered the crud from one part of the system into the part you have cleaned. And around in circles we go. Study the diagrams provided in this thread, think about fluid transfer and follow the manual when bleeding. To assist bleeding, try to get hold of a air compressor vacuum bleeder or at least a hand operated vacuum bleeder. Bleeding the CBS by the hold pump pump hold method can work but will take forever to get right. Once it's sorted, it'll be easy to service every two years. Cheers
There U have it right there what he said...plane as day light.:plus1:
Stex, out
 

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Discussion Starter #29
Ok...i aprecciate all the help but im facing a serious and confusing problem.

I finally got the oil flowing through the rear outer bleeder...AND THE REAR WHEEL DRAG IS BACK. Again, same problem. When i press and then leave the brake pedal with the bike stoped, rear wheel gets stuck for some seconds, then releases for itself, but the excess rear wheel drag keeps on.

Things i have done:

1- Stripped and cleaned all three calipers. Lots of shit inside, but like i said, the bike was having this problem since i bought it and the oil flowed well from the bleeders. Never noticed that something was blocked, except for the secondary master cylinder operation. All pistons from the 3 calipers are working smoothly and i can press them in by hand.

2- Stripped and cleaned secondary master cylinder together with the plastic one way valve.

3- Stripped and cleaned pressure differencial valve (the one near the rear brake reservoir), but it was OK.

4- Stripped and cleaned rear master cylinder.

5 Bleeded the brakes several times following the manual order with the help of a vacuum bleeder. Oil flows strong, super clean and without air bubbles in all bleeders.

With the bike stoped, i press and depress front brake lever, front wheel brakes and releases imediatly, as normal. No drag.
With the bike stoped, press and depress rear brake pedal, rear wheel and front wheel brakes, front wheel releases imediatly as normal, rear wheel gets stuck for some seconds and then slowly releases for itself, but leaving the rear wheel with excessive drag.

Rear wheel is aligned and the caliper guides are free.

I dont know what else to do. I even think there is no more work to be done to the brakes. I`m getting tired of this.
 

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I would pull it off and check it since you have been so thorough with the job. Is it possible the pistons in the SMC and/or rear master cylinder are not retracting far enough to clear the ports, i.e. relieving the pressure in the system? p.s. I walked away from the 'bird a number of times to clear the head and think of :sniper: through the fuel tank! Just think how valuable you will be to the Blackbird community when you have solved the problem :thumb:
 

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Just to be clear - the ONE WAY VALVE in the SMC is actually a TWO WAY VALVE.

The high flow way pushes the ball off the seat to allow the brakes to react quickly.

There is a tiny ( 0.4mm ) hole in the valve so brake fluid can return for pushing pistons back and releasing brakes.

Many people don't clean out the small hole when cleaning out the SMC.
 

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Discussion Starter #33
Just one thing that is bothering my mind...
For what i understand in the cbs tech draw, if the rear brake pedal is pressed with the bike STOPPED, only the rear center caliper piston should move? Am i right?
When i retract all 3 pistons of the rear caliper and then press the brake pedal, all 3 pistons move out.
If there is any air in the system, can the rear brake have this kind of behavior?
I read lots of stuff here in the forum and it seems that many owners had rear brake problems. But i have been looking through all the bolts and bits related to the cbs and i am still facing excessive rear wheel drag and rear brake lock by just using the pedal with the bike stopped.
 

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For what i understand in the cbs tech draw, if the rear brake pedal is pressed with the bike STOPPED, only the rear center caliper piston should move? Am i right?
Yes.
That said, if you look at the second diagram you will see that the pedal also feeds the secondary cylinder (and front centre pistons) so if there is any pressure created in the system through the secondary cylinder the two outer pistons in the rear caliper will operate.

Are the centre front pistons operating when you apply the rear brake pedal?
 

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Discussion Starter #35
Yes...the front pistons are operating.
Last night at the garage, with the help of a pressure plier, i cut the brake oil flow at the rubber hose near the rear brake caliper.

If i cut the flow from the hose that brings the oil from the front, the rear brake is fine. No problems. (I am performing this test just by operating the rear pedal with the bike stopped.)

If i cut the flow from the hose that comes directly from the rear master cylinder to the rear caliper and just leave the oil flowing from the rear master cylinder to the front brakes then into the rear caliper...the rear brake gets stuck and the wheel drags.

I did some research on google about CBS rear wheel drag and found some recalls for this problem with the Goldwing models. Honda changed the secundary master cylinder to solve the problem.
 

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OK so it looks like the problem is still in the secondary cylinder.
It shouldn't allow pressure to 'back feed' and should only operate when the piston is compressed.

Sorry to say it but you need to re-visit the secondary :(
 

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OK so it looks like the problem is still in the secondary cylinder.
It shouldn't allow pressure to 'back feed' and should only operate when the piston is compressed.

Sorry to say it but you need to re-visit the secondary :(
Hi Duck, what do you mean by 'back feed'?
 

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I still think you have crud in the Delay valve or the SMC or PCV. Most likely it is the SMC. Check the SMC piston is retracting fully and not blocking the ports and the check valve is in correctly. This is copied from the folling link. Documents released by NHTSA for the original 2011 recall attribute the problem to a lack of sufficient free play inside the master cylinder that can cause a blockage of the compensating port.

http://blog.motorcycle.com/2015/10/21/manufacturers/honda/honda-finally-has-a-fix-for-gold-wing-rear-brake-drag-issue/
 

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Hi Duck, what do you mean by 'back feed'?
well if only the brake pedal is being pressed that is the only source of pressure in the system so the fluid is coming forwards to the 2 front centre pistons (that's why I asked if they were working) and then finding it's way back to the 2 outer pistons which is why they are emerging from the caliper and causing the rear brake to bind ..... so the pressure is feeding back or 'back feeding'.
This suggests to me that probably the valve in the SMC is not operating correctly.

Note the diagram posted earlier in the thread shows a break in the fluid path at the valve.
 

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OK so it looks like the problem is still in the secondary cylinder.
It shouldn't allow pressure to 'back feed' and should only operate when the piston is compressed.

Sorry to say it but you need to re-visit the secondary :(
I had a think about this and I believe the outer rear pistons should move with just the pedal and then be assisted by the SMC further in to the braking.

When the SMC is in it's fully retracted position - the small port in the side allows fluid from the pedal line - straight through the SMC and out to the rear caliper (outer pistons )
Only when the delay valve has allowed the activation of the front centre pistons will the SMC activate and increase the pressure further on the outer rear pistons.


I think the SMC is not returning fully OR the tiny return hole in the side valve is blocked.
 
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