I came accross this thread while googling an answer to my 44 RC3 Ti knocking. They are a second hand pair I bought in near mint condition, and obviously not used and abused. However, they perform superbly as expected, BUT they have an anoying tapping/knocking noise. I had already stripped/cleaned and put in fresh fluid. All looked very nice inside as I was expecting. But I could’nt live with that small but anoying noise. So stripped them again yesterday to see what could be causing the noise. I refitted the lowers into one stancion only at a time and put oil in as needed, and cyled them by hand. No noise from the spring side, but when I did the same on the damping side (no air pres added) and cyled them up and down, I could hear this little tapping noise. Stripped them again and removed the damper assembly. Obviously this had lost most of its oil, and after a few strokes of the damper shaft, it had lost all of it. But I still could’nt find the noise. This is factory sealed (rolled by machine) so can’t be opened, which realy p*%$ed me off. I was very close to sticking it in the lathe and turning the end off to get inside. But I had one last idea to try. I taped up the multiple hole at the bottom of the damper tube that let in/out all the oil. I then cycled the damper rod up and down fast to the air inside was compressed or sucked, and BINGO a tapping noise from a little insert at the top of the damper tube that is held in with a circlip. The little insert was shuttling up and down, and hitting the circlip, making that noise. I will shim the gap to prevent this, and hopefully have a silent fork.
Reading that some folks have paid for a new damper assembly (£200) to cure this was what drove me to try and find a cure (I’m tight)
The good news is its a cheap fix for what should turn out to be a good fork.