Author Topic: Front Fork Noise  (Read 1114 times)

Offline bikerbob

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Front Fork Noise
« on: 17.10. 2016 19:07 »
I am going to strip the forks on my 1956 A7 swinging arm model over the winter as I have a clattering noise when going over bumps or recessed manhole or drain covers. I need to know what to look for that could be causing this problem, I have checked that nothing external is causing the problem steering bearings mudguard catching and so on. I have strippped this kind of fork down before to renew oil seals etc so am capable of doing the job just need to know what could be the problem, could it be possible that it needs shims how do you check for that. Thanks .

Online Joolstacho

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Re: Front Fork Noise
« Reply #1 on: 17.10. 2016 23:58 »
Hate to be the bearer of (possible) bad tidings but...
Have a really close look / feel of your sliders (fork lower section) around the middle, maybe hold a straightedge up along them. Wear caused by the lower bush can 'bell-out' the sliders over the bushes range of movement in normal running, -sort 'o halfway up. Makes a nice clattering noise.
No cure unless you can find someone who can re-tube them, the sliders are too thin-walled to bore out, not sleeve-able for the same reason.

Offline jachenbach

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Re: Front Fork Noise
« Reply #2 on: 18.10. 2016 01:55 »
Wondering if the "clattering" is the forks topping out?

Offline PaulC

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Re: Front Fork Noise
« Reply #3 on: 18.10. 2016 07:49 »
If it happens particularly over bumps, it can also be the front edge of the petrol tank hitting the top tube.

Paul
A10 Super Rocket 1959
Norton International Model 40 1949
Triumph Thruxton R 2016
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Online KiwiGF

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Re: Front Fork Noise
« Reply #4 on: 18.10. 2016 08:52 »
A feature of the fork design is a clang when the forks hit fill extension e.g when popping wheelies  *wink2* *woo*

Some bikes seem to clang more than others.

At full extension the bushes collide, and there is little/none rebound damping to stop that.
New Zealand

1956 A10 Golden Flash (1st finished project)

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Online ellis

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Re: Front Fork Noise
« Reply #5 on: 18.10. 2016 14:24 »
Surly fitting a pair of damper rods will cure this problem. I fitted a pair to my 1960 A10 with 5w fork oil and the bike is transformed.

Online Klaus

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Re: Front Fork Noise
« Reply #6 on: 18.10. 2016 14:47 »
Note:
If the front wheel is air born, don't be scare...keep up full throttle, so the wheel give a soft touch, comming down. *pull hair out*


This will help solve the problem *yeah*


If you think, everything is under control, you are not fast enought.

Offline bikerbob

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Re: Front Fork Noise
« Reply #7 on: 18.10. 2016 17:39 »
Thanks for all those tips will bear in mind when I dismantle over the winter. Will come back and let you know if I find the problem.

Online KiwiGF

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Re: Front Fork Noise
« Reply #8 on: 19.10. 2016 04:44 »
Thanks for all those tips will bear in mind when I dismantle over the winter. Will come back and let you know if I find the problem.

AS Ellis says, you can fit an aftermarket kit to provide rebound damping, I've not done this myself, but I guess it may solve the "design fault" *dunno* if that is what you are experiencing, I just put with occasional clang  ;)
New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

KTM 950 ADV, cos it’s 100% nuts

1952 Armstrong Siddeley Whitley for rainy days (with wife)

Online Greybeard

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Re: Front Fork Noise
« Reply #9 on: 19.10. 2016 09:54 »
It's the rear wheel that clangs on my Plunger. No damping. Have to try and avoid drain covers and potholes! This is one of the reasons I didn't want to fit a dual seat.

Offline bikerbob

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Re: Front Fork Noise
« Reply #10 on: 22.10. 2016 13:57 »
Had nothing to do today so decided to strip one of the fork legs off. Could find nothing wrong with the bushes stanchions or the fork leg but did notice that with bottomfork leg in the vice and the stanchion fully extended there is quite a bit of clearance between the top bush and the round circlip that keeps it all together I would say at a guess about 1/16". Could this be the source of the noise, have checked and can get shims from Draganfly but should there be any clearance at this point and if so how much . Thanks.

Online Greybeard

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Re: Front Fork Noise
« Reply #11 on: 22.10. 2016 20:07 »
There should be no clearance and that gap is the source of the clonk. Those circlips can be tricky.

Online chaterlea25

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Re: Front Fork Noise
« Reply #12 on: 22.10. 2016 22:19 »
Hi Bob
With that much slack its likely that the top bush lip has been hammered out of shape ???

I fit the bush into the lower leg and then the circlip, then its easy to see if theres a shim needed
I have found very thin shims will fail to stay in one piece in use
So if the gap is less than 10 thou I take a skim off the top of the bush, in order to fit a shim of at least that thickness

John
1961 Super Rocket
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Offline bikerbob

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Re: Front Fork Noise
« Reply #13 on: 23.10. 2016 15:13 »
Thanks for all the advice have completed one leg the gap was less than I guessed a 30 thou shim took up all the play also the circlip is a bit of a bind but eventually succeeded.