Why noise from my right fork?

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DennisMo

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If I bounce the front up and down, there is a metallic fork clunk when the bike goes up and the fork hits its limit.
It seems to come from the right side.
It sounds like the fork has hit its metal sounding limit.
It never made that noise before.
It may be a coincidence, but it started after I took off the front tire to have new rubber put on.

Your thoughts appreciated

Dennis
 
DennisMo said:
If I bounce the front up and down, there is a metallic fork clunk when the bike goes up and the fork hits its limit.
It seems to come from the right side.
It sounds like the fork has hit its metal sounding limit.
It never made that noise before.
It may be a coincidence, but it started after I took off the front tire to have new rubber put on.

Your thoughts appreciated

Dennis
Click to expand...
I recently found my long suffering clunking is the fender stays
 
It will always be the right one - because the other is the wrong one!;);)

...a bit like right side gear change vs. wrong side gear change.
 
Try this experiment.
1) Loosen the axel nut
2) Loosen the pinch bolt
3) Bounce the front end a few times
4) Tighten the axel nut
5) Bounce the front end a few times
6) Tighten the pinch bolt.

See if the problem is gone or has changed.

It may just be a thing you didn't notice before as they do go up against a "stop". It is possible that your front end was cocked (wrong) before and is now right.
 
It happens when I am riding which is how I noticed it. It did not happen before
What were the fender stays hitting??
Dennis
 
Sounds like a Rebuild is in order. When was the last time you changed the oil in the front end leg assembly?
Parts wear out. The top Damper tube cap in particular and the Damper Rod could be pitted causing loss of rebound control.
My guess .
 
I have had the bike since last year and have had many projects but not touched the forks
Dennis
 
CanukNortonNut said:
Sounds like a Rebuild is in order. When was the last time you changed the oil in the front end leg assembly?
Parts wear out. The top Damper tube cap in particular and the Damper Rod could be pitted causing loss of rebound control.
My guess .
Click to expand...
My understanding is that stock Norton forks do not have any rebound control (damping) so have always "topped out" from year dot.
Landsdowne inserts give compression damping in one leg and rebound damping in the other.
 
robs ss said:
My understanding is that stock Norton forks do not have any rebound control (damping) so have always "topped out" from year dot.
Landsdowne inserts give compression damping in one leg and rebound damping in the other.
Click to expand...
"Landsdowne inserts give compression damping in one leg and rebound damping in the other."
Yes I know, I have them.
"It never made that noise before?" so I am giving it my best guess that he is using stock components.
T
 
Last edited:
Its normal for one leg to be longer than the other and the damper rod on that side to reach its limit first. If you remove the front wheel and mudguard , put the axle in from the left (as normal )it should slide easily right in place with finger pressure . But of course it wont ! , To see the extent of the issue rotate the right slider 90 degrees and the left slider 20 degrees and the axle will then run past the right slider hole and you will see the difference , Playing with the locknut at the top of the damper rods and the depth of rod engagement in the top nut will sort it out . You will never need that hammer again and both legs will hit the stops together , or not at all if you sort out the damper holes as recommended . While playing its a good time to change the oil ! . Just done this to my 650SS Proddy Racer . Need to get on with this because at 78 i have only another 10 years or so road racing before i will have take it easy .
 
Last edited:
You need a top out hydraulic bump stop, the factory design got it wrong and the top out limit is the damper valve on the bottom of the rod hitting the damper body top. So fit the longer top bushes so oil in the space between the top and bottom bushes is the hydraulic bump stop.
 
robs ss said:
My understanding is that stock Norton forks do not have any rebound control (damping) so have always "topped out" from year dot.
Landsdowne inserts give compression damping in one leg and rebound damping in the other.
Click to expand...
They do.
 
kommando said:
You need a top out hydraulic bump stop, the factory design got it wrong and the top out limit is the damper valve on the bottom of the rod hitting the damper body top. So fit the longer top bushes so oil in the space between the top and bottom bushes is the hydraulic bump stop.
Click to expand...
If you look up "Norton Covenant Conversion" you will get the details on this omission by the factory
The article is by Peter Crespin (I have a pdf copy if anyone wants to PM me with their email address)
The longer top bushes cover the oil ports before the rebound "clunk"
Cheers
 
robs ss said:
My understanding is that stock Norton forks do not have any rebound control (damping) so have always "topped out" from year dot.
Landsdowne inserts give compression damping in one leg and rebound damping in the other.
Click to expand...
robs ss :
That is not correct.
The stock fork has pretty good rebound damping. It is compression damping that is lacking.
The problem is that the damper cap can wear out fast, especially if the damper rod is not perfectly centered.
This is near impossible to correct, and I doubt many check the rod/valve for concentricity before assembling the fork legs.
 
ludwig said:
robs ss :
That is not correct.
The stock fork has pretty good rebound damping. It is compression damping that is lacking.
The problem is that the damper cap can wear out fast, especially if the damper rod is not perfectly centered.
This is near impossible to correct, and I doubt many check the rod/valve for concentricity before assembling the fork legs.
Click to expand...
Thanks Ludwig - I will have to investigate that further. 👍
 


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