AJS & Matchless Owners Club

I've bought a mostly rebuilt G80 C engine, and I have no idea who took it out of its frame.
Gradually sorting issues out but I have an extra oil union (small) next to the crankcase drain and I haven't yet found its purpose.

Welcome, Steve.
You haven't said the year or show it in your Profile (sometimes the year is important), but exactly which 'union' do you mean?
(I'm assuming it's 'J' next to the drain plug but pls clarify)

Thank you!
It's a 56 G80 C.
None of the parts list I've seen show a second drilling and my G3 only has the drain plug.
My ignorance is about the smaller slanted threaded hole on the right, your D.
Plenty more I don't know of course

I'm pretty sure there's a blanking screw next to the drain plug on my G80S. Which may, of course, be totally irrelevant to your question! I thought, again with no recollection of why, that it related to the drilling for the pick from the crankcase into the oil pump.

Johnny B

I thought that was a possibility but it looks a bit serious for that!
Hoping I dont have to strip it to find out.

on short stoke engine its a blanking plug , nothing else
directly under the pick up pipe

Thank you.
Can't think of anything else logical anyway!