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Discussion Starter #1
I’ve got an 08 Cbr600rr, and I’ve been working on getting my front brake lever more stiff. When I first got the bike the lever would reach all the way to the handle bar even on the highest adjustable lever setting.

Since then I’ve rebuilt the calipers, rebuilt master cylinder, replaced brake pads, installed galfer brake lines and bled it a million times. it’s still very spongey but definitely better than it was.

My rotors don’t seem to be warped. I guess the guy before me put aftermarket rotors on but I did notice that it looks like the rotor is causing the caliper pistons to push out unevenly.
Looking at it from the front end of the bike the two left pistons are way shorter than the two right pistons because the rotor comes so far out. Both rotors are like this and I’m assuming this is why I have such a spongey lever.
I just wanted to confirm this is the issue, also what are some good front rotors to look at for my 08 cbr?
 

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I've seen uneven brake pistons on these many times. Seems to have more to do with one side maybe getting grimier than the other side and thereby adding friction as the pistons move out.

But if you rebuilt yours that wouldn't be the case. Since it sounds like you basically have all rebuilt components this is a real mystery.

But it makes no sense that rotors would play a part unless they're the wrong rotors for the bike. Which is unlikely since you'd have fitment and clearance issues.

Maybe you have the left and right rotors on wrongs sides.
 

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Discussion Starter #3
Yeah I’m not sure. I will take pictures when I get home to help explain but idk if the guy before put wrong rotors on, but the rotor itself pushes so far out from the wheel that the only way the caliper will properly seat is if the two left pistons are practically closed.
 

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.........but the rotor itself pushes so far out from the wheel that the only way the caliper will properly seat is if the two left pistons are practically closed.
That does not sound right at all. The disc should be central in the caliper body.

Best discs to replace with? Honda OE discs, every time.

New discs may not solve your problem, but I would strongly recommend you change them Don't take chances on brakes.

Another possibilty is that your master cylinder is worn. I put a rebuild kit in the M/C of my 2001 ZRX1200R and it made things worse! The bore was worn. So needed new M/C.
 

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Discussion Starter #5
Was there any noticeable wear or scaring in your mc. When I rebuilt mine I didn’t notice anything but at this point I’m willing to try anything lol
 

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Discussion Starter #6
It’s a little hard to tell but do you see what I mean? Idk if it’s possible that the previous owner put some random rotors on here but it’s almost like both rotors lift too far out from the wheel.
225269
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Was there any noticeable wear or scaring in your mc. When I rebuilt mine I didn’t notice anything but at this point I’m willing to try anything lol
I couldn't see any.

Hard to tell from your photos, but disc should sit central in the gap in the calipers.
 

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Hard to tell but are inboard pistons extended on both sides?(then too much rotor offset) if not then the wheel is offset somehow?
 
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