Need Help With Front Rotor Drag


Hey now I'm totally desperate! I've rebuilt both calipers and installed new break pads. I even went as far as purchasing a new left caliper and I'm STILL having drag! uggh...on the stand I can spin the wheel about 2 full revolutions before it stops...I get on the freeway and go about 3 miles..pull over and the right disk is cold...the left one is on fire! At this point I have no idea what to do...any one have some suggestions??

2002 Hayabusa...9k mods...completely stock
You can test it if you have a run out dial indicator.

When you apply the brakes,I'm guessing you feel a pulse thru the lever,the more braking pressure applied,the more the pulse.

Absolute true test. Remove the wheel,put a peice of steel in between the pads to act as a rotor. A peice just big enough to cover all the pistons.Drill a few holes to hold it in place with some mechanics wire or strong zip ties. Go for a ride,no more pulse. Replace rotor.

You may also have a collapsed brake line on the caliper that is sticking. Sometimes rubber brake lines collapse inside. Under pressure they will flow, but they can act as a residual pressure check valve, leaving a few psi in the caliper. It doesn't take much to create a little drag.

I may have some stock rubber hoses in my garage, you are welcomed to them if you want to try different brake hoses.
I can't be certain if they are perfect, but it woudl be mighty coincidental if two sets were bad on the same side.

Question: When you ride and apply the brakes, then ride a little more and reapply, does the lever seem to require any more travel or do you have to pump it to get the lever to tighten up? A warped rotor will force the pads on the warped side apart, when then requires repumping them down the next time you brake. If not, then it's not likey the rotor. Why one would be stone cold and the other one really hot is interesting to me. What it really sounds like is one of the calipers needs rebuilding as it's stuck; since it won't compress, the other side is carrying all the load.

There is a specific proceedure not found in the owners manual that Dave Moss teaches in order to ensure you center the wheel before tightening the goes something like this:

1. Install the wheel and tighten the axle temporarily with both sets of pinch bolts loose.

2. Install the brake calipers, torque and pump the brakes till they seat. Some people apply the front brakes firmly, then tighten the caliper bolts to ensure they are centered over the rotor.

3. Torque the axle bolt using a wrench and a special tool to hold the axle.

4. Tighten and torque the right side pinch bolts.

5. Pump the front end (at the triple tree) up and down a couple of times.

6. Tighten and torque the left side pinch bolts.

This method makes sure the forks are not pinched inward while torqueing the axle and gives the proper amount of free play in the hub stack.

Comeon Tuf, post up....
:welcome: to the oRg :thumbsup:


My experience is identical to divers. I'd lose front brakes, pump them up and loose them if I rolled the bike a few feet. You could actually look through the nose and see the disk moving left and right.

I believe one of two things might be wrong. Spacers on front wheel installed wrong, or stuck piston (s) on caliper. I don't know chit
Yeah...I'd totally take them...I've been paying really close attention to it all since I read all the posts...No on the pulsing and all over the breaks feel kinda I'm thinking that the lines may have collapsed on the left side...additionally I replaced the left side with a totally different caliper and still getting drag. So if your offering I'm willing to try anything at this point.
Comeon Tuf, post up....

"Are you gonna post up soon Tuf? Are ya? I hope so, cause your my hero. I mean yer Tuf,that why they call you Tuf right? And that RSD guy,well he knows nothing right Tuf! You should post up because he did and he is wrong because he aint Tuf like you! Right Tuf?

Damn, wasn't it Keith Code in "Twist of the Wrist II" who said "Be cautious about how you digest advise off the street"?

Skydivr is nuts on. It's so very quick and easy to check for a bent rotor. It's all in the lever. And just to clarify, a bent rotor won't cause the rotor to overheat. It takes friction to create heat. A bent rotor pushes the pads away from the rotor so there is no friction except at the extreme limit of the bend in the rotor creating very little heat.

Sometimes neglected brake calipers will eventually accumulate enough crud around the pucks that the inner Oring cannot retract the puck away from the pad properly and can create excessive drag. I first thought this was most likely your problem. But since you just installed a rebuild kit, I'm sure you cleaned the pucks up eliminating that issue. The Oring is what does the work. When you apply the brake the puck extends rolling the Oring with it, when you release the pressure the Oring rolls back into place bringing the puck with it. The movement is so slight its hardly noticeable with the naked eye. My best guess is you installed the Oring dry, not allowing the Oring to seat correctly and it cannot do its job properly.

Your brakes should create some drag when functioning properly but not enough that you cannot hold your hand on them.

Your OEM brake lines are not made of rubber. They are made from braided nylon and rubber coated. They work exceptionally well under normal use. Steel braided lines are designed to maintain their composure under extended hard use which you will only find on the race track. Steel braided lines have little if any advantage for street riders.

One more point, OEM lines do not collapse. They may rupture from the inside out but the braided nylon will never collapse.
Long time ago, I changed pads, rotors and new OEM calipers because they were all worn out. About 3 months later, I ended up with a warped rotor. How could that be with all new parts? Turns out after lots of money spent and heartache, it was a defective caliper. It can happen.
"Are you gonna post up soon Tuf? Are ya? I hope so, cause your my hero. I mean yer Tuf,that why they call you Tuf right? And that RSD guy,well he knows nothing right Tuf! You should post up because he did and he is wrong because he aint Tuf like you! Right Tuf?

How much time did you spend on that Rubb? That's actually pretty funny!

However, I'm still trying to figure out how, but asking one member for their opinion, I somehow offended another? I asked Tuf because I have been at the receiving end of a lot of his knowledge, and he knows a LOT about bikes. We actually had this exact same discussion a year ago when I thought I'd warped a rotor too, and after explaining it to me in detail giving his time and attention, it made a whole lot of sense. I actually thought he might be able to help the OP and save him some $$ at the same time.

If you look at the timeline, I don't see how you can conclude I was baiting you in any way. Having said that, when I see you put a pass on him at the racetrack, then I'll be glad to follow you around like a little puppy too.....
Sooooo, you like being a little puppy :poke:

:rofl: you guys kill me in here at times, but after working all weekend and putting up with all the BS complaints, and whining in general from people that can not take care of themselves and have no control over their lives what so ever and feel the need to dial 911 daily, it's good for my soul
More likely you have a sticking caliper, see the other post about rebuilding calipers. The hoses do swell from the fluid, internally swelling shut so fluid can be forced in but it can't return to the master but they usually last over 10yrs before that happens unless you are using some cheap crap fluid that swells rubber. An easy way to check is to open the bleeder, if a little bit of fluid bursts out like it was under pressure and the wheel frees up then the hose is probably the problem. If the wheel doesn't free up the caliper or pads are probably sticking.

Another way to check them is once you remove the hose blow compressed air through it with an air blow gun, just wear safety glasses and be careful where you are pointing it, best done away from the bike or cars as they tend to wiggle and spray fluid all over the place and if totally clogged can blow fluid back at you. Cover blow gun with a rag where it is inserted into the hose. If air doesn't flow freely through then they are swelled closed. You should only do this if you are a trained professional, but then... you would already know how to do it.:laugh: