That will probably be the Eddie Dow or copy two way damper similar to that sold by Goffy http://www.norbsa02.freeuk.com/goffyfork.htm Did similar to my 1952
Hi, First of all what have I got in my 1957 model? Dismantling the right hand fork leg to get the cowl off I find I have a damper rod attached to the top nut.
SRM recommend running on 40 or 50 sae oil and are worried that high pressures from a faulty filter may damage their pump. Not a risk they are prepared to take.