Clunking Forks

madass140

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I've had a couple of customers who after fitting the Lansdowne dampers have complained
about a "clunk" when the forks change direction at compression. A customer of John's had
the same issue and found it was caused by end float of the lower bushing, the same cause
with my customers. In John's case and also mine the fix is to Loctite the lower bushing on to the stanchion
to stop movement, even .010" end float will cause the clunk,
Don
 

Scout63

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Don - does this happen with stock rebuilds? Mine clunks when I put it on the center stand. I rebuilt with AN internals.
 
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FWIW, my (stock build) forks also clunk on the center stand. from what I understand, this is somewhat normal. doesn't seem to affect anything during the ride.
 

madass140

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Don - does this happen with stock rebuilds? Mine clunks when I put it on the center stand. I rebuilt with AN internals.
It very well may, but the noise will be enhanced with Lansdowne dampers. The clunk on the centerstand may be the forks
bottoming out at full extension
Joe czech its annoying but no it wont affect the performance or do any damage
 
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Don - does this happen with stock rebuilds? Mine clunks when I put it on the center stand. I rebuilt with AN internals.
That clunk is the damper valve on the end of the damper rod hitting the underside of the cap on the top of the damper body caused by a design flaw. Cure is fitting a longer top bush or a sleeve inside the top of the fork lower, this reinstalls the hydraulic top out bump stop by trapping oil between the upper and lower bush.
 
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Mine stopped 'clunking' on the centre stand lift when I renewed the oil.... Not sure what the internals are, I assume 'OE' :)
 

robs ss

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I've had a couple of customers who after fitting the Lansdowne dampers have complained
about a "clunk" when the forks change direction at compression. A customer of John's had
the same issue and found it was caused by end float of the lower bushing, the same cause
with my customers. In John's case and also mine the fix is to Loctite the lower bushing on to the stanchion
to stop movement, even .010" end float will cause the clunk,
Don
Don
Do you mean loctiting the bush to the stanchion or the alloy leg?
Fixing the bush to the stanchion doesn't appear reasonable - at least to me.
 
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Thanks for this Don, will give it a go. I have experienced a fair bit of clunking since fitting your Lansdowne's last year.
 

concours

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It very well may, but the noise will be enhanced with Lansdowne dampers. The clunk on the centerstand may be the forks
bottoming out at full extension
Joe czech its annoying but no it wont affect the performance or do any damage
Mine clunks over the road (with Lansdowne dampers).
 

johnm

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Mine had a clanking sound during operation on one leg.

On inspection you could see the spring was hitting the damper rod as it compressed and moved sideways.

Firstly the end of one spring was not machined at right angles to the length and was twisting over when compressed. So this was remachined.

Secondly we made tight fitting Teflon sleeves to fit at two points on the damper rod thus centering the spring.

After this no more clanking.

You have to be careful to measure the positions of the lock nut system which locates the caps with the damper adjusters otherwise the rods will be outside a suitable adjustment range.
 
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That clunk is the damper valve on the end of the damper rod hitting the underside of the cap on the top of the damper body caused by a design flaw. Cure is fitting a longer top bush or a sleeve inside the top of the fork lower, this reinstalls the hydraulic top out bump stop by trapping oil between the upper and lower bush.
Replace the damper caps sometimes called top hat bushes while you're at it only a couple of thou wear in the bush will allow enough oil to bypass and cause the clonk. RGM do a cast iron version.
 

madass140

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Don
Do you mean loctiting the bush to the stanchion or the alloy leg?
Fixing the bush to the stanchion doesn't appear reasonable - at least to me.
to the stanchion before you fit the circlip,why doesnt it appear reasonable?
 

APRRSV

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that is why I posted the problem and the fix
Hi Don,
Was/is this also a problem with the original Landsdowne dampers? I mean no disrespect. I have purchased several of your parts and find them to be excellent.

Ed
 

madass140

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yes. you can find the same info/issue right here on Accessnorton from many years ago when John was onboard
 
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