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I have a four caliber beringer front brake and a beringer radial master cylinder and a beringer 310mm brake rotor ("floater") set up from 3bros. racing out of Temecula, CA on a 07' exc450. After going through hard whoops at Evergreen, Monroe, WA I lose front brake pull going into the next corner. Front brake almost pulls all the way to the bar. Then corner two brake feel is back. Blead the snot out of the line, so almost 99.99% sure no air in brake line (new line). Air temp. not that hot I feel to cause brake fluid to get too hot. My shop guy told me on bent wheels or bent rotors they wobble and push out the pistons on the front caliber and can do this to the brakes. I have a feeling the 310mm rotor (so called floater) is a used one and is too "loose" and causes this. Any input would be nice. I've felt other duplicate rotors on bikes and they dont feel as loose as my rotor. Thanks
 

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That's what I was thinking, that the rotor is either warped, bent or loose and floating around and moving the pistons back.

I'd take the rotor off and see if it is warped. Or find someone who will let you swap front wheels and see if it does the same thing. If it does do the same thing, there's another issue.

(On the :infrandom :infrandom side of things, you could just ride a wheelie through the whoops and not have to deal with the brake fade. :lol: )
 

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Motoul RBF 600 brake fluid... buy some

I had the same symptom (which I believe is boiling the brake fluid)

the RBF boils @ 600*

I havent had a problem since I changed my fluid...

warping would be a pulse in the lever, not losing line pressure...I think the wheel would have to be spinning significantly fast to cause the pistons to 'float'
 

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not to repeat what they just said, but sounds like the rotor is warped... or atleast moving enough to push the pads away from the rotor..

if it was brake fade, it would come in when the rotor/fluid/pads got hot (not just one turn, and whoops wouldnt effect it)



you said it was loose.. thats probably fine. but make sure EVERY button is the same amount loose.. if one is tight and the others are not, it can bind sideways.. and since its rotating, that pushes the pads back.
 

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like mrdude said, make sure there isn't anything stuck in one of the buttons. the beringer rotors are full-floating, that's why they move so much. the new beringer rotors have spring washers in the buttons and don't move laterally nearly as much as the older ones. my bike has had 2 full race seasons on the same cast iron rotor and i've had zero issues with warpage. the full beringer set-up should by design pull the pistons back a little when the lever is released. the symptom you're describing happens in road racing after a tank-slapper, so I would double check to make sure you're front wheel is running true and make sure there isn't anything that could have been on the mating surfaces when the rotor was mounted to the wheel. Also you may be able to buy an upgrade kit from beringer that has the new buttons w/the spring washers to keep the rotor from moving so much that its forcing the pistons back into the caliper. a small pump of the lever after a heavy whoop section should bring the pistons back to where they should be but that isn't something you should have to be doing during a race.
 
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