I have a zx12r 2012, today I took it to the dealer for all fluids to be flushed and the bike now does stops as aggressively like it used to, i remembered touching the front Brakes and the bike went down and stopped quickly now I just ride it for a few miles and it feels weird different it brakes but not the same way. This was done in a Kawasaki dealer. You think they did something wrong?

How does the lever feel? Maybe caught a bubble, maybe did not bled the master's nipple?

Try a zip-tie tied down for a day/overnight? See if the lever pressure changed? Usually shops are open on Tues so the zipped brake lever shows no joy, can take it back and have them bleed it?

I can count so many combinations that should change a feel of the brakes, but can't come up with anything to correlate it against. Not even a harsh road test after the bleed.

Changing out pad to a set of old disc might show something, but as far a poor performing brakes after a fluid change? Kind of leads to air in the line compressing a bubble first before the fluid.

I replaced my brake pads as about 12k miles. I don't remember which brand/model pads, but I think they were EBC HH maybe? At any rate I know they were high performance. I did the fairly standard bedding process.

For me, they seemed to have less initial bite than the OE pads and an overall different feeling. Overall my perception is that in overall power there is no difference, it seems just like in the initial application they seem less stoppey. I'm not positive on any of this, and have no actual measurements of stopping distances or anything along those lines.

I don't know what it seems like exactly. As Hub mentions, could it be installing on unprepared rotors? Could it be they are different pads? Could it be some combination?

I don't think for me at least, it could've been air bubbles since I usually flush and bleed the brakes every year, although since that was several years ago now I don't recall EXACTLY how things went down, I do know at least the fluid would've been changed within the last year then also flushed and bled at the time of the pad change.

I remember asking here at some point about trying to prep the rotors, I suppose similar to your typical auto rotor and that I recall no one really had any thoughts on it. I think it could be ideal to at least hone the rotors, but I don't know how that would be done...is that even something pro shops can or do?

I didn’t replace the pads i left the shop and i noticed the front brake was harder than normal and not stopping like it used to, so the zip tie procedure is pressing the front break real hard and keeping press with the tie? What is that supposed to do?

Wait a minute. You are now saying: "the front brake was harder than normal." OK, then the zip-tie is to bring back a harder level if it had a soft lever feel to it. What the zip does is applies pressure to the line, moves the air up the line and traveled up to the master. When the zip is cut, the piston in the master moves back, exposes the hole so the air moves back up into the reservoir by floating to the surface.

Maybe you had a soft lever all this time? Now you feel how it really should feel.