Engine oil leak

Any thoughts on root cause of this annoying leak on my Spada. It had 2 bad leaks which I’ve fixed (engine dipstick, gearbox breather) but this one is still there.

I thought it was the sump gasket, but seems to be coming from above the sump joint. Oil gathers around joint between engine and flywheel housing, and also seems to be wet round the back right corner at the bottom of the block. Doesn’t seem to come out of the weep hole at the bottom, although I may be wrong about that. The sump looks to have a weld repair in the corner. I keep hoping it’s residual oil from before, but it always seems to re-appear when I clean it off. Photo is after it’s been standing for a couple of hours after a 50 mile ride.

I’m thinking I’ll have to have a look at the rear seal?

Hi Ian
Are there any track marks from the top of the case?
I can lay my hands on a spare sump to try out if you wish.

I can’t see any oil above the first rib on the block. Do the holes for the sump bolts break through? Maybe getting up the bolt thread? I think I have another sump in the box of bits that came with the bike.

I’ve seen hairline cracks which have let a bit of oil out.
Sumps come in for a lot of abuse from over-tightening, knocks and people hammering them until they find out about the long inner bolts :astonished:
good luck