Dodgy brake disc?

[lynnnsr]

I have Honda NSR125 2001 which I am doing a few jobs to.

My question is about the front brake disc. It is in two parts - one outer part where the pads rub on it and an inner part which bolts to the wheel. The two parts are joined by a series of metal rings at various points around. I think this is pretty standard for sport-type bike.

Problem is, when the brake is on, the wheel can still be moved around very slightly, can't easily see the movement but can definitely feel it. There is movement between the two parts of the disc. I'm guessing it's and MOT failure like this, but can the disc be repaired / tightened somehow or is it new disc time?

Thanks
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NSR 125 (with L-Plates) > 1994 NTV 650 > 2015 CB650F > 16 VFR800F

[Taught2BCauti...]

I'm pretty sure that a small amount of movement is intentional, and is designed to allow the friction contact surface (outer part) to run true under braking, even if there is a slight mis-alignment of the wheel itself.

The reduced contact area between the inner and outer parts, would also lessen the amount of heat transferred to the hub bearings and grease.

If you are worried about it, have a word with the local dealership for advice on when it needs to be binned for a new one.
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Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[wr6133]

Those bobbins on the disk should have some movement (you should be (just) able to rotate them by hand).

[Ridersofthest...]

Yes its correct, have someone look into it if you think its to much.

[UrbanRacer]

They are called floating brake discs. They are like that to reduce vibrations and to reduce the chances of them becoming warped

[Polarbear]

As said, floating disks. You shouldn't be able to wobble them but feeling movement is fine.
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Triumph Trophy Launch Edition

[spannermonkey...]

Is the front wheel bearing good?

The discs are designed to float on the bobbins but not to much.
Problems come when the seize up.

They can do it with the aid of weather and give a warped disc feel on the brake lever.

They can also be caused by when you brake hard and generate a lot of heat causing a few bobbins to seize and it feels like a warp the disc on the brake lever, but when checked with a dti sometime after the ride it's straight and true.
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Current machines - Aprilia RS250. Kawasaki H1A 500. Past machines - Kawasaki ZX7r P6, Yamaha RD250E (the one that got away), BSA Racing bantam (revs over 10'000 sweet as), Yamaha RXS100, Suzuki GP100, Suzuki GS500K2 - best all year machine ever - come rain, sleet and snow just epic.

[lynnnsr]

Can't detect any movement in the bearing and the wheel turns freely.

disc doesn't give any real side to side movement and the bobbins can all be (just) turned by hand.

Movement in the disc is probably acceptable then bearing in mind what's been said on here about the ideas behind this sort of setup.

I'll take it for an MOT and see what's said...
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NSR 125 (with L-Plates) > 1994 NTV 650 > 2015 CB650F > 16 VFR800F

[Pete.]

Some bike makes are more prone to loose discs than others. If it passes muster at MOT time, just put up with the rattle.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Islander]

[HughiusMaximu...]

Have a look at this for info on how to clean the bobbins.

https://www.youtube.com/watch?v=1qoPqN2GBdw

Its actually a very good channel - lots of advice on basic repairs and maintenance.

[lynnnsr]