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Hi all. Quick question. I used this method after installing my braided hoses last night. Bled brakes with "old" 1 month old brake fluid and then flushed with a brand new bottle (Motul RBF 660). Both bottles of brake fluid same type.

No air in system at all down towards calipers but I noticed the top bleeder by brake lever has the tiniest air bubbles and I bled there about 8 times in total until I had finished the bottle. The feel on lever is 80% stiff on setting 1 (the hardest setting). Could my master cylinder or something be faulty? The bike had the recall work done earlier this year by previous owner. Bike is 2005 Suzuki GSXR 1000 k5.
 

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Hi i am restoring a Rgv250 and it has new lines and rebuilt calipers. Brakes bleed fine and the lever feels good and stiff. The issue is after i let it sit 1 minute the brake lever needs to be pumped up again. Basically seems like air is entering when the lever is in its at rest position. The interesting thing is if i zip tie the lever no fluid leaks out and it holds pressure. I suspect the master cylinder but i have loolooked at it and don't see any faults.... any thoughts please


 

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Moto-joe, I can't thank you enough. Seriously, PM me your paypal email and I'll buy you a beer. My k8 750 had a spongey lever when I bought it. I got the master cylinder recall done, still spongey. I put braided lines on and bled it with the open the bleeder/crank/close method. firmer lever, but still no feel. at my major service I mentioned it to the tech, and he claimed "they are all like that". so I was resigned to crappy brakes on a bike I loved everything else about.

Well, I had a spare bottle of brake fluid after reading this method. all I can say is Genius. sure it's not a Brembo master cylinder with monobloc calipers, but it is decent for a factory system. feel and firmness is good. Thanks again
 

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i did a caliper rebuild today on my 05 gsxr 600. my brakes are still mushy after doing the steps in OP's guide. i ran more than a reservoir through and saw no bubbles. it may be a leak somewhere causing a loss of pressure. i will have try again tomorrow and look for a leak.
 

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i did a caliper rebuild today on my 05 gsxr 600. my brakes are still mushy after doing the steps in OP's guide. i ran more than a reservoir through and saw no bubbles. it may be a leak somewhere causing a loss of pressure. i will have try again tomorrow and look for a leak.
Doubt it, it's probably just residual air in the system.
 

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Doubt it, it's probably just residual air in the system.
so I should just bleed them over and over and over? when do i stop bleeding them and decide to do something else besides just bleeding them repetitively? at what point does one do something else besides attempt to remove air from the system?
 

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so I should just bleed them over and over and over? when do i stop bleeding them and decide to do something else besides just bleeding them repetitively? at what point does one do something else besides attempt to remove air from the system?
If you had a leak in the system, you'd have different symptoms, but you can take your calipers off and inspect them for a leak. Brake bleeding requires patience and the right technique, otherwise you're always going to have a mushy brake lever.
 

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If you had a leak in the system, you'd have different symptoms, but you can take your calipers off and inspect them for a leak. Brake bleeding requires patience and the right technique, otherwise you're always going to have a mushy brake lever.
you weren't kidding. after rebuilding the calipers, I ended up going through nearly 2 bottles of prestone and no matter what tried i would get those bubbles that look like carbonation, very tiny, and never ending.

i ended up buying an accossato master cylinder, some motul 600, and a vacuum kit. i cleared all the prestone from the system. then i pulled motul into the MC but couldn't get it totally clear. pulled fluid into front right, about 97% clear. pulled fluid into front left, 97% clear. one more time, same thing.

so i pulled the nipples one at a time and wrapped them up about 6x with thread tape, ran a lighter over it for a second, put them back, bled them again and then they finally began to bleed clear. did the same with the MC and it bled clear.

Now it has a soft feel until it grabs, then it is very firm, almost no mushiness. 10x better than before. i think this will help with later braking.

i need to test other brake levers to see how they feel. my duke 390 doesn't have the same soft feel for the first 50-60%. it's a bit more firm.

thanks for the guide.
 

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Hi guys, (sorry for my english I am from Czech Republic)
I have GSX-R 750 K2 and I was hate my front brakes - cause rubber hoses and if i remove brake pads - there was chinese sh*ts :D .I was buy new brake pads SBS compound HS which is street syntered (maybe try RS compound after this). Last summer I was riding with new pads and brakes felt a little bit better but rubber hoses are spongy. Next I was buy HEL lines in winter. Now I have a little bit firmer lever but if I pull hard I can pull the lever by the bar :( I done everything and I beleive that I was doing it right!

Brakes and MC stock
Calipers inner cleaned - not rebuild new seals
MC inner cleaned - not rebuild kit used
Brake pads SBS HS
Brake Lines HEL Performance race setup newly installed
Fresh brake fluid MOTUL RBF600

I try bleeding from this thread. Everything looks good but lever is not too stiff what i want. So I was finding on other forums and threads. First I try remove calipers, pads and pull pistons in caliper 60% out - everything was clear offcourse. Net push pistons only by fingers down and hope that flow can bubles up to reservoar. Nothing better. Next because my MC have not bleeder i can try bleed it by the banjos on the MC. No nothing was better and lever was not stiffer. Last what I will do over this night is tie the lever and hope that I have some bubles in the system and they go up to the MC and when I open the reservoar and let thle lever - bubles go out and I will have stiff lever and I will go to stopie with one finger.
 

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Now I cut tie, op?t reservoar and see no bubles. After that I crack the banjo bolt by MC and bleed. Try bleed both caliper and no bubles. So after that all I am sure that my system have not bubles inside. But lever stiffnes is about 60% and if I want I can pull hard and her lever completely by the bar. Mayebe will be better when I ride, hope.
 

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It sounds to me like you have a leak somewhere, or warped rotors that are pushing the pads back causing you to lose pressure.
 

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Could be...
 

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Positioning on that model doesn't require a bleeder on the MC. It bleeds itself back up through the reservoir. I think if you want better, you'll have to go with an aftermarket MC.
 

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I am back :)
I was bought Touramax repair kit for my bike GSX-R 750 K2 today. When I was remove piston from MC and see on my new piston I was fed up, because previous owner must crashed that bike and buy MC from another bike. For first look both MC´s are pretty similar, but on my bike is MC Nissin 14mm piston and originaly MC Nissin 15.8mm - so my problem with soft brakes was too small piston in MC - fu*k this guy.
I was call to my friend who rides on track and he have one MC from his R6 09´ - it is 16mm piston MC from radial Brembo and fits well on my bike (I know that OE Brembo is not aftermarket Brembo but from OE Suzuki axial to this Brembo is good uprage).
Tomorrow I will go ride and test how I feel with brakes and wrote my experience with R6 MC, HEL lines, SBS pads HF Street Excel and stock Calipers.
 

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:)
I was testing brakes today - COLD weather about 8°C and brakes are awesome vs stock! Radial pump from R6 is big improvement and HEL lines offcourse too. SBS HS have good initial bite, good feel and I know what front brakes realy do. Front rotors looks better more consistent (united) surface(before I have really shine rotors cause small pressure on pads only polish rotors) now I can brake!!! I can set the brake lever shorter and brake wit two finger easily - only touch the lever and brakes react (with axial sure not :-D) I can easily brake hard, as hard that the rear wheel goes up and I can finally smile to the helmet.
 

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Hi guys,
Good weather is here and I have little bit brakes fade. I have SS Lines HEL, SBS HS pads, OEM calipers and radial MC Brembo from R6 09 - and yes I was bleed system properetly and have fresh fluid Motul RBF600 DOT4. SBS HS pads are street oriented, can be problem here? Next pads will be SBS RS, but my HS are still new.
GSX-R 750 K2 hard street riding
 
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