A65 Rear Chain Oiler from Primary Case

[Whalen]

Hi, my 1971 A65 Thunderbolt has lost the rear chain oiler that is bolted into the back of the primary side case. Making a real mess with oil coming out onto surrounding area.
I'm thinking to plug the hole with a bolt - parts list says 1/4" UNC.
Is there a 1/4 UNC elsewhere on the engine I can try to see if it fits?
Tried a bolt from the same position on my B40 but it seems too small diameter.

If I take the primary chaincase cover off, can I see the oiler hole from the inside?

[Gup holland]

Yes here a picture from the inside, small hole

[Gup holland]

When clutch is fitted

[Tigerfeet]

I find the chain oiler on my A50 to be invaluable. I have never oiled the chain in 20,000 miles. It will occasionally leave a drip on the floor when parked - but that reassures me that the oiler is still working.  I'd source a replacement - rather than blocking it off...