Join Date: Feb 2002
Location: OKLAHOMA CITY OKLAHOMA
I have found this to be a somewhat common problem on r1/r6's.
They do have a bit more brake drag than other bikes.
On my r1 when i notice the brakes dragging I just unbolt the calipers and clean the pistons and the seal (without taking them out!!).
Do not EVER push the pistons inside the calipers without cleaning them of all grime first. It will shove some of the grime into the caliper bore. This is an often overlooked step. Most people just shove the dirty pistons back into the calipers to put new pads on without cleaning anything.
Unless you have too much fluid in the syatem, bleeding the system will not help cure brake drag.
Use emery cloth or fine sand paper to clean the pistons throughly. 9 times out of 10 it will free everything up.
Also you can take the brake pad spring on top of the caliper off and throw it as far as possible. It is there to help fight brake noise, but I have no noise and have not had them on in 30k miles.
Take the brake pad retaining pin and clean it, best is to use a wire wheel on a bench grinder but you get the idea.
When you put the caliper back on the disk, first pump the brake lever a few times to make it just too tight to fit over the disk. Then slowly wobble the caliper over the disk, letting the disk spread the pads slightly. This may sound counter intuitive, but I assure you it is correct.
Ever notice that your lever travels a bit more than you would like, or more than it used to? You still have the same brake power, but the lever has to physically move farther than it did before to get the pads biting on the rotors. Here is the reason why, and the reason I say to pump the lever before instillation and use the disk to spread the pads:
There is a square section rubber seal that seals the brake fluid in the calipers, and more importantly is solely responsible for pulling the brake pads away from the disk when you let off the lever (or pedal). See when you apply brake pressure and the pistons are driven out of the calipers it distorts the rubber seal, and when you let off the lever the seal has some spring energy as it is streached out, so the spring energy brings the seal back to it's normal shape and brings the piston back with it. It does not pull the pad back, but without any pressure on the pad the bike rolls freely (plus the vibration will help kick the pads out a bit, a very small amount).
Now what happens it that as the pad wears the piston is meant to slip past the rubber seal farther and farther, so that the same lever travel is always used to get the same result. In the real world though the seals will dry out a bit and stick to the pistons, and they will not let the pistons slip past the seal any. What this means is that as your brake pads wear you have to use more lever travel because the pistons are being pulled back into the same old pisotion as it always has been, even though the pads are thinner now and have to move farther to touch the rotors. This makes you move the lever farther before the pads bite onto the rotors.
By pumping the lever a couple times you will break the seals hold on that particular position on the piston, and force it out farther than it needs to go. The piston will be wet where the seal touches it now, and as you use the disk to spread the pads the piston will move back only as far as is nessairy, and the result will be a firm lever with shorter travel. Just like it was when it was new.
So long story short, push the pistons out a bit and clean them throughly with emery cloth. clean the brake pad retaining pin so that the pads can slide smoothly. Throw away the copper colored spring (it traps heat and brake dust), and use the disk to spread the pads out to where they need to be.
You do that to both sides and you will once again have a free spinning wheel, and a firm lever.
If you have a new bike (or brake system) you may not notice the lever traveling any less than before. That means that either the seal is not stuck to the pads or the pads have not worn much yet. This is most usefull to bikes that are a couple years old and in need of brake service.
I Pray I am strong enough to never give up.
Worry about doing what is right, and let someone else worry about everything else.