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307 Posts
Discussion Starter #1 (Edited)
I have a lot of free travel/dead zone at the lever, have to adjust it all the way out and cant reach it. Pumping the lever yields a creak as the caliper pushes one brake disc sideways until it reaches the other pad.
Just replaced and rebuilt calipers(ninja 650 with sv seals), and MC(R6/brembo). I have the same setup on my track SV and get almost no free travel and less drag, the wheel spins 1.5 more rotations.

-Checked for leaks
-Pads are flat, also tried another set
-Bled a couple bottles of fluid through, also bled with the pistons pushed in.
-Doesn't seem to be the pistons retracting too much. I tried the trick to eliminate seal flex.
-Swapped caliper slide bracket in case it was bent, it slides very easy.

14 Posts
I'd suggest a caliper and/or master cylinder rebuild.
If only one side is pushing out and retracting the join between the two sides of the caliper may be blocked.

I didn't have such a drastic problem but my calipers were starting to stick so pulled them apart and the far side from the banjo bolt on one caliper the brake fluid had turned to jelly and some of it was interfering the passage where the o ring between the two halves sits too

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480 Posts
I have had a similar issue since rebuilding my MC. Maybe you still have an air bubble in your MC. I've recently found this procedure that seems promising:
First off make sure your rotors and the other stuff is up to spec. Levers functioning the same as OEMs, Correct brake fluid, calipers clean, master properly cleaned and no blocked passages, rotors straight, bottoms are all free so ring can properly float, rotor ring is not a Belleville washer, pads are not worn like a wedge.

If I had your bike in the shop as it sits, this is what I would do.

Burp the master:
Set lever to the furthest out position possible
Grab a spare clip on bar and remove master and mount to a spare bar.
1. Holding the master horizontal to floor pump a few times and hold pressure.
2. Tilt the bar 90 degrees up while holding pressure (in a way that it would be like you just knocked the bike over on the left side).
3. smack the end of the bar that is pointing up with the back end of a big screw driver or similar.
4. Tilt the bar 45 degrees and release lever.
5. pump lever 3-4 times rapidly.
6. Hold bar horizontally again and pump a few times.
7. Repeat a few times
8. Remount brake master.

This process works the air bubbles that get caught in the spiral of the piston back into draw section of the master and a bubble or two will burp out into the reservoir line.

Once this is completed I move to the calipers.
Make sure all brake pistons are clean and free to move and scrub with soap and water around each piston.
1. Set fluid level in reservoir
2. Pull one caliper off and remove pads
3. Hook up a hose to the bleeder and zip tie the line so a loop stays in the line and then drains into some container.
4. Hold caliper at the angles and such to approximate how it would mount if the bike was vertical.
5. Crack bleeder open
6. While holding the caliper, now hold the upper pistons from extending and simultaneously squeeze in the lower 2 pistons.
7. Now hold the lower pistons in, and squeeze the upper pistons in at the same time.
8. Close bleeder
9. Slide pads in temporarily
10. Pump master until all pistons have equally extended and pads are squeezed together.
11. Repeat this three times
12. Install pads
13. Install caliper and torque to spec.
14. Now repeat on the other caliper.
15. Now pump up brakes
16. Bleed once at each caliper bleeder to eject any little bit of air left at the bleeder.
17. Fill fluid.

This process forces air that has been trapped in the lower piston bores to move to the upper bores and then squeezed out through the bleed way. I often get a tiny little area of tiny bubbles that come out, rather than seeing just one big bubble.

This is also the process I recommend for flushing brake fluid. Think about bleeding in fresh fluid. It just comes in from the banjo and out the near by bleeder without actually purging out the nasty fluid that is stagnant in the piston bores. I have done this on “freshly flushed” brake systems before and gotten super stinky jelled up fluid coming out of the calipers.
Source: Front brake issue - SV1000 Portal
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