So i have a pretty serious front vibration/stutter at all speeds. It's not just under hard braking, even with just light braking going at super slow speeds coming to a stop, it feels like there is front brake slip, like there isn't a consistent contact patch on the brakes. do you think this is a warped rotar? visually it doesn't look warped, but i haven't pulled them off to check. I replaced the brake pads.

does anyone have suggestions? should i scuff the rotors up with some sandpaper to check the contact patch?, should i pull off the calipers? any diagnosis or suggestions would be greatly appreciated.

fyi it's a 2000 cbr600f4

 

when was the last time you sanded your brakes
sometimes brake pad material will build up on the rotors creating a high and low spot
get some wet dry sand paper ( wet it ) and sand the rotors
also take your brake pads out and clean your calipers
you can take the glazing off the pads by simply rubbing them across your smooth garage floor
give that a shot
if that doesn't do the trick you may have warped rotors

 

As you have already replaced the brake pads, it won't have anything to do with them so I would check for disc warping as suggested. Any easy way is to fix a pointer to one of the fork legs so that it is almost touching the disc and by turning the wheel you should see any noticeable gaps if the disc is warped. Ideally you should use a dial gauge if you can get hold of one and place the plunger onto the disc, zero it and then turn the wheel. The gauge dial will move noticeably if the disc is warped. You may have loose steering head bearings which might be worth checking out as well. When you replaced the pads, were the pistons easy to push in to accommodate them? I'm thinking that maybe one of more may be sticking? See how it goes and let us know.

 

thanks for both suggestions, i will pull the pads and clean the calipers in the next couple days, then as said check the disk with a dial guage. I didn't even think about doing that, so thank you for the suggestions. I'll snap a few pics in the process and report back in a few days. thank you for your help

 

so as a test to check the rotors warpage, i put marker on the rotor then did a turn of the wheel with the brakes lightly pressed to see if there was an area where there was no contact, but it seemed fairly good. however i pulled the pads and pressed in the brake lever to take a look at the pistons, and the top piston is coming out smoothly, but it seems like the bottom one is sticking as it doesn't come out at the same rate. Both pushed back in ok, but the top is definitely moving more smoothly.

suggestions?

 

So i forced the sticky piston in and out a couple times put the pads back on and went for a quick spin and the vibration seems to be gone! we'll see how long it lasts! thanks again for the tips, i wouldn't have thought to check the pistons otherwise.

 

Glad everything turned out ok for you! We can't always think of ways to solve problems-hence this forum! LOL! Hope you don't have any more problems.