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jays22b

front disc loose 07 yz450f

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i have never felt a slack spot in front brakes before. reason i notice it as i just rebuilt swing arm and head stem and thought some thing was loose there and i found the fualt to be in the front. i know there is ment to be flex in the disc but i have 1mm off movement in the disc, its off and clean and i can not see there wear but can move the center 1mm around. Is that normal?

http://i847.photobucket.com/albums/ab40/jays22b/discoff.jpg

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i have never felt a slack spot in front brakes before. reason i notice it as i just rebuilt swing arm and head stem and thought some thing was loose there and i found the fualt to be in the front. i know there is ment to be flex in the disc but i have 1mm off movement in the disc, its off and clean and i can not see there wear but can move the center 1mm around. Is that normal?

http://i847.photobucket.com/albums/ab40/jays22b/discoff.jpg

Yes it is normal, check another bike even a new bike. With the front brake applied the wheel will rotate about 1mm back and fourth due to the floating disk button setup. I had the same question about a month ago :busted:

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I wouldnt say they are meant to be "flopy" yes a bit of movment, but generally if there is alot of play and or a metal clunking noise then your bushes maybe stuffed. New disk. Alot of aftermarket ones avaliable.:busted:

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I wouldnt say they are meant to be "flopy" yes a bit of movment, but generally if there is alot of play and or a metal clunking noise then your bushes maybe stuffed. New disk. Alot of aftermarket ones avaliable.:busted:

Yeah thanks mate, I think it moves too much i find it hard to believe nobody can give up a way off checking wheter there's too much play in it.

I can only see the play it has now only getting worse ever ride i do, so i might have a play with this disc and see how little play it needs to be a floating disc.Close up the floating points as much as i can. worse case i buy i new disc.:thumbsup:

when i take the disc to work i might sparks it and see what the disc is made off. If anyone wants to know pm me and will send test through. got a AU3million dollar tester at work and i love seeing what steels are made off.:banana:

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Just reached over in the toy hauler and grabbed my 07 YZ front rotor I would say it has half an inch of play measured at the end of the rotor or say 14.mm

My 09 KX250 same way. Wifes 09 honda is fixed does not flex

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Just reached over in the toy hauler and grabbed my 07 YZ front rotor I would say it has half an inch of play measured at the end of the rotor or say 14.mm

My 09 KX250 same way. Wifes 09 honda is fixed does not flex

That is a large amount off play compared too mine, This play in the front disc would have to effect the braking ability, finding it hard to believe it is a good setup.

What was the advantage off being floating disc. Sports cars dont have em, any other braking system I've ever seen on anything keeps away from this style?

Would it be possible to use a solid version off this disc? The back disc is solid and performs great.

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I'm guessing you don't hit many things with your front disc when you ride. I've crammed front end into rocks and logs and disc just goes back to center when you come off. Also they claim under hard braking it isolates resonance from the rotor to the hub resulting in no brake squeal or vibration. For what it's worth never had a warped rotor on a floating setup unlike my CR's of old

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The true purpose of floating the rotor on its center is to allow it to heat and cool without the thermal expansion leading to warpage and distortion of the center. It's quite common with light gauge, large diameter rotors.

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The true purpose of floating the rotor on its center is to allow it to heat and cool without the thermal expansion leading to warpage and distortion of the center. It's quite common with light gauge, large diameter rotors.

fair enough, gap should close up when the disc gets warm. Not enough to cause warpage or resonance from the rotor. got it and will leave it the way it is.

Thanks for the feedback

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