Surging front brake. where to start?

[mowgoli84]

Alright, as some of you know I recently picked up an 08 1125r. More than last time I made sure I looked for all the little things when I test rode the bike. Both tires have good tread, but have massive chicken strips, telling me that this guy wasn't any kind of speed racer, all stock. The only thing, the front brake pulses, or surges, lerches, whatever you wanna say when you apply it.. even at very low speeds.
I have been told that it might be because the front tire is flat spotted. Bearings seem good, caliper, and rotor are torqued.
Where to start, tire? Rotor? Pads?

I tried to find a thread but failed, there probably is one, so if there is direct me that way lol

Thanks

 

[Junkbone]

Heat/glaze/ scorch marks on the rotor? Also I had a bit of a surging problem like this on my XB. I first took my dremmel tool and a cone shaped bit and counter sunk all the round vents in the rotor. That fixed it in that case.

 

[uly luigi]

there is a coupla threads, but first thing I would do is take a green scotchbrite and some wd40 and scrub the rotor at the same time replace pads with lyndall golds, you will, 90% of the time, fix the pulsing, if it don't, EBR hardware is the next step

 

[Riderdie]

Check if the rotor is still "floating". Push on it at the mounting points see if the springs are working correctly. I ended up having to replace mine when it was pulsing b/c it was warped. When I took It off and layed it on a flat surface I was able to rock it, the new one sat flat.

 

[mowgoli84]

Thanks guys, I will check it out. hopefully its a simple fix. I do like the ebr rotors tho

 

[Riderdie]

Check if the rotor is still "floating". Push on it at the mounting points see if the springs are working correctly. I ended up having to replace mine when it was pulsing b/c it was warped. When I took It off and layed it on a flat surface I was able to rock it, the new one sat flat.

 

[TooFst]

+1 to riderdie

 

[uly luigi]

low milage, nonaggressive rider, I'm betting dirty rotor

 

[buellbradski]

I had a little surge last year scotch brite and new pads solved it

 

[Doosh]

> if it don't, EBR hardware is the next step

Unlikely. If the issue is lack of hard use and pad deposits, this won't help. And, it might make it worse, since the EBR hardware is very particular to the wheel being especially true -- much more so than the spec in the service manual.

 

[infamouscrew02]

I fixed mine, I doused the contact points/springs with wd/40 and let it sit. I also took fine sand paper and sanded on the disk. So far no more surging for me. Make sure your careful at first when you go riding, YOU WILL NOT HAVE A FRONT BRAKE UNTIL THE WD/40 WARES OFF!!!!

Dont go ripping down the street into a turn, you wont be able to stop. Ride around the neighborhood at slow speeds dragging the front brake.

 

[mowgoli84]

I fixed mine, I doused the contact points/springs with wd/40 and let it sit. I also took fine sand paper and sanded on the disk. So far no more surging for me. Make sure your careful at first when you go riding, YOU WILL NOT HAVE A FRONT BRAKE UNTIL THE WD/40 WARES OFF!!!!

Dont go ripping down the street into a turn, you wont be able to stop. Ride around the neighborhood at slow speeds dragging the front brake.

Gonna get to it here in a little bit. Thanks for the input!

 

[Doosh]

Pull the hardware an inspect it. If the "square" drive bushings are showing uneven wear or the rotor's bearing edges are worn, replace both.

The drive bushings wear ahead of the rotors, and if they are anything but perfectly tight need to be replaced.

The OEM setup on these bikes promotes the drive bushings coming out of square, so it's something to keep an eye on.

 

[mowgoli84]

Well I scrubbed the rotor, and hit the float spots with some cleaner. It was smooth as glass for about 30 miles, then some surging came back, but I would say its about 70% less intense, or more. So at least now I know its likely the pads and not a warped rotor. Pads appear to be factory.
Now I just gotta decide on pads.

Thanks all for the good input.

 

[jimijeans]

While you are checking your Brakes make sure to check the Steering Head Bearings after that checks out you can Bleed the brakes first make sure theres no air making it pulse. Then after you bleed them Firmly tie (don't kill it), the Lever in the Braking position for at least 6/hours then this way you know if the Caliper has a piston that's Sticking or if the Brake Hardware needs to be Replaced. Go With Erik Buells Brake Rotor Rebuild Kit It works great. Most Likely the Rotor Hardware needs to be Replaced. Make sure to use a Hand Impactor to Remove the Torx Bolts so none Wringe off at the Bolts heads. One Drop of Loctite]Blue[ on the New Bolts in the middle of the bolts will keep them from backing out. I lay the Rotors here at the Shop on a LARGE piece of glass to check for warpage. Non Stock Brake Pads will work better as well. Lyndall has some great pads for street or Track Day Applications.*Jimi

 

[mowgoli84]

@ JIMIJEANS [up][up][up]