Oh man. Ever since I got the K-tech cartridge I notice this clunk noise. I am hoping it is something like a loose steering head bearing. It sounds like it is hopefully different from your experience. I hear/feel it at low speed when I hit a bump.
That's the one. The road I live on is quite bumpy, plus there's a traffic cop who lives quite close, so I ride off super slowly in the morning and all I could hear and feel was this knock/rattle as the wheel moved over the bumps quickly 🤦. At first I thought a brake pipe was slapping the mudguard, then like you I thought it was the head bearings. Then I wondered if the pads where rattling in the brake calipers. Eventually I realised it was my super expensive 'high quality' new fork cartridges. Insert expletives here.
The good thing is that according to K-Tech our forks are functioning correctly. I.E the damping is working just fine, so apparently it's nothing to worry about. Once I knew that I quickly started to push towards the edge of the rear tyre in corners, so they definitely work fine.
K-Tech apparently did a lot of research to understand what was causing the noise and they figured out it was a little return spring inside the check valve. They designed a new one and fitted it for me many months after their first attempt to repair them. If you get in touch with K-Tech they will probably help you out. If their customer service is as good in North America as it is in the UK, they should do it for free, including paying the shipping both ways for you 🙂.
As I say, the noise hasn't completely gone away, and it's worse in colder weather, but it's better than when I first got them. Good luck 🙂.
