This is the jet holder that screws into the inner timing cover and retains the big end feed plunger - This is also used for the similar item on the racing cambox bevel cover for holding the camshaft oil feed jet holder.
It is also the same type as those fitted to pre 1938 OHV/SV timing covers, of the type that were fitted with round external jet holder nuts. Pre-war the Norton part number for this item was 9012 and pre-38 was all models. Note: OHV/SV civilian models 1938 onwards changed to a plain timing cover with different Bigend quill and holder. Sorry we do not make that holder type yet, but can supply the later OHV/SV quill - Item 0964
Likewise, pre-1938 the OHV/SV engines used a round jet holder nut with screwdriver slot (part no 8750), while SOHC models used a hex nut which we sell - Item 0068). We do not manufacture the round nut yet . .. you can try the hex type, but check it does not catch the timing cover - email us if you require the round type, it is on our list of parts to make.
If you are reading this listing from our OHV/SV section - please view the the SOHC Timing Case section for other parts to go with this quill holder