Fork rebuild

Finally got to it, last spring came too quick and an (fork) oil change was all it got. Took it down, some obvious worn parts, some questions. The stanchion tubes are toast.. pitted with rust (I had stoned the pock marks previously to minimize damage) and wear. Once I got them out, it's clear they're both bent too.. about .040"



The bush on one side looks like someone struggled with it at one time..

Unlike the smooth wear marks as expected, found on the other one.


The oil seals are TRIPLE LIP... are most of them supplied like that? Even MFG. and size/PN on the back!

One of the damper rods has curious dings in it, (a LOT of them, like 30 marks) unlike the longitudal scoring/scuffing you'd expect, like the other one has. Any guesses why? I don't have the answer yet, and forensic mechanics is my job.



Someone tried to tighten up the bush with a center punch..



One stanchion tube had a ding so big on the bottom, I had to stone it for 15 minutes to get the lower bush off
(post remediation image) Think someone dropped it?

Guess the marks are from a vice :?:

john robert bould said:

Guess the marks are from a vice :?:

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Yeah... that's likely. Not the usual staggered diamond pattern from vise jaws, but likely clamped in some soft jaws a bit too loose. Good call!

The marks on the inside of that bushing look like it may have been twisted back and fourth over the bad spots on the end of the stanchion? Also agree that the scars on the damper rod are from a vice or pliers.

MikeG said:

The marks on the inside of that bushing look like it may have been twisted back and fourth over the bad spots on the end of the stanchion? Also agree that the scars on the damper rod are from a vice or pliers.

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Yeah, like three thread teeth together. Slid right off these stanchions. Maybe previously stuffed?

And what about these long bushes from Clubman Racing? Has anyone used them? Work as advertised? From their website:

"Guide (Upper Bronze) Bush Upgrade - One of the errors in the description of the operation of the Norton forks in the Commando Workshop manual tells how the upper fork bush covers the larger of the two holes in the fork stantion as the forks are near full extension, slowing fork action and preventing the forks from "topping" out. This never happens because the bushing is to short to reach the hole before the forks are fully extended. We now offer a pair of longer bushing that greatly reduces topping and also supplies additional support to the stantions. To prevent increasing "stiction" the center section of the bushings are relieved to provide only approx. the same contact area as the originals. (A rebuild kit as above but with the extended bushings will be available shortly) #N020 - $34.95"


And on the same idea.. looks like fastback is using spacers to acheive the same effect? Anyone give more info on this?

I tried the spacers below the bushes and the so called covenant fork upgrade, relocating the holes on the damper. But in my case I had no real improvement. The marks on the bushes are from PO using a pin punch to install them, not good! The alloy caps on the top of the dampers are critical to rebound, so the damage to your damper rod will have damaged them I suspect.
A great upgrade, if you like modern feel and adjustable forks is the Landsdowne damper kit. It would be a great time to spend on that rather than replacement parts like damper rods and caps etc. Another thing I have fitted is teflon main fork bushes. You can purchase items from JS Motorsports or if you are a lathe nut like me, you can make your own. The Teflon certainly allows the fork to slide effortlessly even under side loads, thus makes a really nice compliant ride when coupled up to the improved dampers. Only downside is after you have done this, you will want to upgrade your rear shocks!
Richard