NC30 Fork rebuild

I’ve been collecting parts to start working on the NC30. The first step was to fix the leaking fork seals.  This turned into a bit of a longer project after taking the forks apart and noticing that the slider bushings were in pretty bad shape, too, so I figured I should just replace them while I had the whole thing apart.

Old fork seal

This is what the old fork seals looked like, split and rusty. I don’t know what could make them look like that, except maybe if they were driven in with a screwdriver or something that damaged them. Hopefully it’ll be a while until the new ones look like that…

Fork bushing

The fork bushings were in pretty bad shape, too. This was admittedly the worst one, but there were clear signs of abrasion so I figured they should all be replaced as well.

While I had the forks off, I also disassembled the steering head bearings to clean them out. They were in decent shape, with this glaring exception:


One of the steering head bearings. Note the huge flat spot on the ball in the center! This must have been preexisting, because there’s no way you could do that to the ball without damaging the races, which had no signs of abuse.

I don’t know how you make a ball look like that, but I suspect it must be a manufacturing defect since all the other balls and the races look fine. The top dust seal was torn so I replaced that too. (It wouldn’t have hurt to replace the bottom one but you can’t get that one out unless you remove the lower race which I wasn’t about to do.)

Finally, I also replaced the dust seals on the front wheel bearings which were pretty crusty (and had been painted over which I’m sure doesn’t improve their flexibility)…

After putting it all together and taking it for a short test drive, everything seems to be fine. No noticeable play in the steering head, no noticeable stiction in the forks. I still have to tune in the fork preload and damping, but it’s probably easier to do that when the bike is fully running…


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