Forks twisted?

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Steve6088
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Forks twisted?

Post by Steve6088 »

I have recently fitted some cbr900 forks. I've just been out for a ride and the bike rides terribly. The steering feels 'wobbly' and steers differently from right to left. Bike feels like it wants to fall over when you turn right. Could this be that the forks are twisted? if so does anybody know how to allign them?

The front discs are catching even though I have put spacers in, could this be causing this?

Any suggestions much appreciated.
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lloydie
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Re: Forks twisted?

Post by lloydie »

Its worth measuring the gap between the fork leg and the discs on both sides (they should be the same )

To check if the forks are twisted Remove the front wheel . Slacken the top and bottom yoke bolts .
Hold the fork lower in place and turn the chrome leg around and see if the bottom moves in a Oval patten if it dose then the forks are bent .

Also worth checking the preload is set the same on both forks .
And they are the same hight in the yokes . And the dampening is set the same .
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Steve6088
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Re: Forks twisted?

Post by Steve6088 »

Thanks for suggestions.

I have tracked down what it is now. The forks look to be spinning in the top and bottom yokes. When I hold the wheel between my legs and move the bars I can get them to move and the wheel wont.

I have done both of the clamps up as tight as possible but they still spin 8O . What could the cause of this be?
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lloydie
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Re: Forks twisted?

Post by lloydie »

So what your saying is with the forks clamped in the yokes there is movement at the wheel .
If this is the case the fork bushes need renewing .
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lloydie
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Re: Forks twisted?

Post by lloydie »

Or is it you can't get the yokes to clamp up tight enough ?
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Steve6088
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Re: Forks twisted?

Post by Steve6088 »

lloydiecbr wrote:Or is it you can't get the yokes to clamp up tight enough ?
I can't get the the yokes to be tight enough. The forks can become missaligned if you fix the wheel and push hard on the bars. I'm presuming it is due to this anyway. I cant think of anything else :?
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lloydie
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Re: Forks twisted?

Post by lloydie »

measure the forks they should be 45mm .
but it sounds like you might need replacement yokes .
was it all ok before you removed them ?
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Wicky
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Re: Forks twisted?

Post by Wicky »

VTR = 41mm forks

CBR = 45mm

So must have already different yolks - Can you describe the parts more and where they're from on your front end swap.
Last edited by Wicky on Mon Nov 05, 2012 1:38 pm, edited 1 time in total.
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AMCQ46
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Re: Forks twisted?

Post by AMCQ46 »

I agree, they should be 41mm, but if the leg can move in the yoke i suggest you dont ride it again till you work out what is wrong.
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Steve6088
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Re: Forks twisted?

Post by Steve6088 »

Yokes and forks came straight off track bike I dismantled. They were straight and fitted okay then, so I'm a bit puzzled.
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dragonback
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Re: Forks twisted?

Post by dragonback »

well my first thought was your bearings but stick some pics on and id like to see the thickness of your forks,have you measured forks , yolk
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NHSH
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Re: Forks twisted?

Post by NHSH »

AMCQ46 wrote:I agree, they should be 41mm, but if the leg can move in the yoke i suggest you dont ride it again till you work out what is wrong.
+1 Don't ride with the legs loose like that, this is really not safe at all!!!
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Steve6088
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Re: Forks twisted?

Post by Steve6088 »

I have undone the yokes and then done then back up again even tighter and there is no movement in them at all now. Atleast that is sorted.

But the bike still has the wobbly turning symptons. I have tracked it down to the loose steering bearings as I can feel them click when I push the forks forward with the brakes on. Does this sound the likely cause?

I have used needle roller bearings on the bottom of the steering stem and standard ball bearings on the top, is there any chance this could cause problems? I couldn't see why. I will try just tightening the bearings up a bit more if not.
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Wicky
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Re: Forks twisted?

Post by Wicky »

Steve6088 wrote:I have used needle roller bearings on the bottom of the steering stem and standard ball bearings on the top, is there any chance this could cause problems? I couldn't see why. I will try just tightening the bearings up a bit more if not.
I think each need different torque, so having a mix will cause potential problems - as if you torque one up correctly the other will be slack. Why not install a fresh pair of one or the other for safety sake.
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Xenocide
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Re: Forks twisted?

Post by Xenocide »

Steve6088 wrote:I have undone the yokes and then done then back up again even tighter and there is no movement in them at all now. Atleast that is sorted.

But the bike still has the wobbly turning symptons. I have tracked it down to the loose steering bearings as I can feel them click when I push the forks forward with the brakes on. Does this sound the likely cause?

I have used needle roller bearings on the bottom of the steering stem and standard ball bearings on the top, is there any chance this could cause problems? I couldn't see why. I will try just tightening the bearings up a bit more if not.
That might be worn bushes in the forks themselves :)
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