i have a 03 CBR F4I, i changed the rear pads and the brakes stopped working, i tried to bleed them but no matter hom wany times i do it the pressure never build up even though air came out of the line.

this might help
compressed piston, to get the new pads on
accidently bleed for first time like you would on a car
pads are on correctly

 

first check for fluid leaks...then check to make sure the bleeder is screwed in tight and no air or fluid is leaking out....then check the banjo bolt at MC and at the caliper make sure nothing is leaking there...

if it's all tight....and nothing is leaking....

then it might just be a time thing...let me explain....the rear MC pumps very very very very little fluid with press of the level...if you compressed the piston into the caliper, the piston has to extend to its normal position before you will get braking out of it....that means you have to fill the caliper with brake fluid, then once full, continue to pump the level to move the piston out until it reaches the rotor....this can take a looooong time....because there is so little amount of fluid moving with each pump of the lever, it may take 100 or 200 pumps before you can reset the piston in the caliper...

now...there might be a greater problem...but from what you have said i can't be sure....make sure the brakes are bled properly so there is NO air in the lines...make sure everything is tightened up after bleeding and pump that lever a good 100 times or so and see if it doesn't start to firm up a bit....if it's STILL not firming up.....remove the caliper and see if the piston has moved out at all....if it hasn't, there are other issues, if it has moved out more than it was previously, just continue pumping, eventually you will get your brake back...

make sense?

 

Before you start pumping, take off the cap, and open the bleeder. Let gravity do its thing for 10 minutes or so ( i like to run the res nearly dry at least once), then start the pumping procedure. Also make sure that everygthing is still sitting right. You may have put the pads in right, but maybe it got bumped a bit, or the caliper is not on perfectly straight.

 

good point teeks....i was assuming that during bleeding, he let "gravity do its thing"....i shouldn't really assume that....the thing i am thinking is that initially something was just installed wrong with the pads and then when you bled, something went wrong with the bleeding or you took for granted what pushing in the piston all the way would do...

either way...i would (personally) re-bleed the brakes making SURE they were done right...then go to town pumping!