Judder from front under Braking (not disc warp)

[BlueBird]

05,abs,70k up it.

I am getting serious judder through the bars when braking heavy (which i like to do a lot) the ends of the bars are actually moving back and forth violently and its feels like holding on to a jack hammer,it also feels like the bottom of the forks are "walking" to and fro or at times going in a figure of 8 movement.

The front shock is showing oil leakage on the damper rod


So I have checked the discs (from steptoe) and they are within tolerance,wheel bearings,bottom balljoint and bolt tightness,top yoke bearings and bolt tightness,if fact ive checked everything apart from tightness of upper frame to engine which I will do today and it is all in good nick apart from shock.wheels are balenced and tyres,TR91s (excellent) are correct pressure.

only thing left is bushes on stanchions,

Im finding it hard to understand it could be knackerd shock causing this,

Anyone else had it or any ideas

 

[TeaPig]

You have checked everything I can think of and the stanchions are easily tested by elevating the front of the bike and heaving front to back to see if there's any play.

You haven't unknowingly bent a fork leg have you?

A completely knackered shock can allow a wheel to bounce under braking but I agree it would be surprising if this the problem. Also, I've had car wheels that do this, which when swapped cure the problem. It's as if the wheel balance changes dynamically as the tyre is heavily loaded.

Perhaps the only way forward is by substitution starting with the shock and then the disks, even though you have said they are within tolerance. Is it worse when the brakes are hot? Any sign of slight judder when used gently or only when used hard?

 

[trainman]

05,abs,70k up it.

I am getting serious judder through the bars when braking heavy (which i like to do a lot) the ends of the bars are actually moving back and forth violently and its feels like holding on to a jack hammer,it also feels like the bottom of the forks are "walking" to and fro or at times going in a figure of 8 movement.

The front shock is showing oil leakage on the damper rod


So I have checked the discs (from steptoe) and they are within tolerance,wheel bearings,bottom balljoint and bolt tightness,top yoke bearings and bolt tightness,if fact ive checked everything apart from tightness of upper frame to engine which I will do today and it is all in good nick apart from shock.wheels are balenced and tyres,TR91s (excellent) are correct pressure.

only thing left is bushes on stanchions,

Im finding it hard to understand it could be knackerd shock causing this,

Anyone else had it or any ideas

maybe one caliper has an issue - have you had the pads out and checked for stuck or corroded parts?

it can always be the simplest thing as i know to my cost

 

[BlueBird]

cheers

I have the old discs and will try them
and also overhaul the calipers,Im not one for washing bikes and they are minging with brake shite.

 

[wust588]

Front wheel bearing, or knackered ball joint perhaps?
Best of luck.

 

[Berg]

Try to rub down the brake disc with sandpaper and then clean with brake cleaner

 

[BlueBird]

Try to rub down the brake disc with sandpaper and then clean with brake cleaner

yes tried that,no difference,

Im away for 2 weeks so will look at it when I get back,im going to invest in some new shocks aswell.

Another problem that brings though,

Ohlins or Wilbers!!!!!!!!!!!!!!!!