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Measuring fork slider wear .

Posted: Wed May 14, 2025 4:43 am
by Giles B
Hi all, I have a 1983 g/s which has the front end clunk noise which has been discussed many times on forums online. I have tried all the possible fixes suggested other than fitting the last modification of fitting the mk3 damper internals which people have said is not a cure . Mine has the mk2 internals with 7.5 wt fork oil. I was wondering if some of the noise was being caused by worn fork sliders. I don’t know a way to measure the diameters of the internal bearings or other way to ascertain if they worn.They are not the original sliders as they have been replaced with used ones before. The chrome stanchions are in spec .The manual states that stanchion dia should be 36.050- 36.075 and the slider internal dia should be 36 +0.25 .Even if the sliders are not causing the noise it would be good to know ,so any suggestions would be appreciated .

Re: Measuring fork slider wear .

Posted: Thu May 15, 2025 6:33 am
by SteveD
That's some very specific info needed in a system that doesn't get a lot of love other than occasional part swapping...my guess.
Sorry, can't help. I did find a very good video from Brook Beams rebuilding a ST fork, but that didn't have your answers.

https://youtu.be/edcv4Nm0LoU?t=318

Re: Measuring fork slider wear .

Posted: Thu May 15, 2025 8:53 am
by gspd
Giles B wrote: Wed May 14, 2025 4:43 am I was wondering if some of the noise was being caused by worn fork sliders. I don’t know a way to measure the diameters of the internal bearings or other way to ascertain if they worn.
The age old method of 'measuring' is rocking the front axle back and forth with the wheel in the air, with the springs removed, so you can test at full compression, full extension and everywhere in between. There should be no discernible play throughout its full travel.