How to remove an internal dent in the fork leg ?

Phil-UK · Post by **Phil-UK** » Sat Mar 30, 2013 8:26 am

Hi

Picked up a set of early CB72/77 forks ( with the steel sliders ) and on each fork someone has used too long a screw in the mudguard bracket. This has caused the lower bush on both to be smeared but also left what feels like a bump/dent/dimple on the inner face of the fork leg using a thin straight edge running down the inner surface.

Has anyone got a method to remove these bumps given the lack of room between the fork outer and the metal tube that sits inside it ?

It seems too far down the fork to get at on a lathe, but I'm open to any suggestions,

thanks

Phil

mike in idaho · Post by **mike in idaho** » Sat Mar 30, 2013 11:31 am

I would turn out a metal plug, tapered on the edges, equal to the diameter of the fork bush with a threaded hole in it for attaching a slide hammer. Coat the plug with anti-seize or grease and drive it down behind the damage. Tap the surface of the fork leg around the mudguard boss to help raise the dent in the tube. Use the slide hammer to withdraw the plug afterward, use a brake cylinder hone to finish.

G-Man · Post by **G-Man** » Sat Mar 30, 2013 4:04 pm

Phil

Common problem. All of the people on the forum who struggle to dismantle these forks has this problem......

I have successfully used a long grinding bit in my dremel to work away at the dimple if it is the top screw.

You cannot push a solid plug in there as the spring guide is welded into the centre of the fork slider.

You might be able to make a tubular lap. You could use the old fork bush now that it's buggered.......

If you cut a few grooves in the bush, loctite it to the fork tube, smear on some grinding paste and then work it in and out with a rotary push-pull action, that could work.

The other solution is to drill right through the screw hole and take out the dimple that way. I did that on one of mine. You would have to use a thread sealant on the bolt thereafter but you will reclaim a scrap part.

G

rrietman · Post by **rrietman** » Sat Mar 30, 2013 6:29 pm

I hane done this repair several times on cb160's. patience and a rat tail file is a low tech fix I have had success with.
Randy

Phil-UK · Post by **Phil-UK** » Sun Mar 31, 2013 5:51 am

Thanks Guys ... will see which method looks easiest to do on my set, if I can reclaim a pair that would be good.

cheers

Phil