K100 front wheel off centre?

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krankshaft
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K100 front wheel off centre?

Postby krankshaft » Thu Feb 18, 2021 9:35 am

Hi, fellas
I recently changed both front discs and pads on my K100 and now the wheel is not spinning freely when lifted
off the ground. It is rubbing the brake pads (the right one in each caliper)
I measured the distances from the seam in the fork and the wheel is off to the right by a bit more than 2mm.
Maybe it`s always been like this and it wasn`t an issue until the new thicker EBC discs and pads were fitted.
Has anyone any thoughts? Should the front wheel be offset?
Thanks for any suggestions.
Ride safe
Jim

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Rob Frankhamr
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Re: K100 front wheel off centre?

Postby Rob Frankhamr » Thu Feb 18, 2021 11:42 am

I think the first thing to consider is that any offset of the wheel in the fork should not affect the action of the pads as long as no piston or pad grounds in the caliper... and by that I mean that the piston/caliper assembly doesn't meet up with any resistance when it retracts. This being the case, and assuming that you put everything back exactly as it came off, it is quite possible that your wheel has always been a couple of millimetres off centre (rightly or wrongly) and the rubbing brakes are due to other issues.

The first thing to look at is whether the pad and piston on the affected side of each caliper can be moved further back into the caliper. If it can't, then the issue becomes whether that's because it's as far back as it can go or whether the movement of pad or caliper is limited by corrosion on the caliper, debris inside the caliper cylinder, corrosion inside the cylinder, corrosion on the piston or simply because the pads are too thick. If they can move back a bit but move back onto the disc and rub after a brake application, you are again looking at corrosion or dirt in the caliper or piston.

There is also a possibility that and obstruction in the balancing port in the master cylinder might cause brakes to rub although the specifics of this issue make that less likely in this case.

Going back to the position of the wheel in the forks, it is well worth checking that the fork legs are parallel. It is very easy, when fitting a wheel, for the action of tightening the axle nut to pull the opposite fork leg out of alignment if the axle isn't free to move in the fork... especially if the 'mechanic' tightens the pinch nuts before tightening the axle nut... I've seen that done 'so that the axle doesn't turn when I tighten it'... :roll:. It can also happen because the axle binds in the forks due to dirt or corrosion. Bouncing the forks with the pinch bolts loose will normally correct the problem but on extreme occasions, it may be necessary to measure the distance between the forks at various heights up their length to ensure that they are parallel.

Rob
Robin Frankham
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krankshaft
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Re: K100 front wheel off centre?

Postby krankshaft » Thu Feb 18, 2021 12:51 pm

Thanks, Rob
I think I've found the problem...bent spindle!
The spindle has probably been bent since I got the bike but hasn't been noticed as it hasn't caused problems.
I think this time with the new pads and discs and the spindle being in the worst position it has been worse.
I moved the spindle about and found a position where it has least offset and it spins freely.
Will try to find a spindle and will be using my R80 for a while.
Thanks again.
Ride safe
Jim

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Rob Frankhamr
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Joined: Mon Jul 25, 2005 6:33 pm
Country of Residence: Scotland
Location: Kinloch Rannoch, Perthshire

Re: K100 front wheel off centre?

Postby Rob Frankhamr » Thu Feb 18, 2021 6:27 pm

Thanks, Rob
I think I've found the problem...bent spindle!
The spindle has probably been bent since I got the bike but hasn't been noticed as it hasn't caused problems.
I think this time with the new pads and discs and the spindle being in the worst position it has been worse.
I moved the spindle about and found a position where it has least offset and it spins freely.
Will try to find a spindle and will be using my R80 for a while.
Thanks again.
Ride safe
Jim
Yoy may be aware already but in case you're not, the front wheel spindle (axle) is common to all K100 models, K75 models and Monoshock 'R' models with the exception of the K1 and the K100RS 4V

Rob
Robin Frankham
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Frankhams retirement home for elderly Boxers.

krankshaft
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Posts: 155
Joined: Tue Dec 16, 2014 10:53 pm
Country of Residence: switzerland

Re: K100 front wheel off centre?

Postby krankshaft » Thu Feb 18, 2021 8:27 pm

No, I didn`t know that, Rob, thanks.
I was looking at motorworks/bins/sherlock and they only seem to have used parts, so I sourced a new one
locally. Expensive but it will come quickly.
I remembered that I hit something on the road years ago and buckled the front wheel, I`M guessing
that`s when the axle got bent, it is not much but enough to throw the top of the front wheel over by 2mm at the worst
position and I hadn`t felt the effect til thicker discs and pads were installed.
Thanks again for reply and I`ll let you know how it turns out.
Ride safe
Jim


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