Leaking oil tank

[Alfow]

Hi all,

I bought my bike with an oil leak from somewhere around the bottom of the oil tank. The previous owner had stripped to a point then given up.
I took over, fitted new gaskets put it back together and got it running. Checked it over and there was oil coming from the l/h side at the bottom of the oil tank behind where the solid oil pipe bolts in.
Stripped it down again expecting to find a gouge or similar in the mating surfaces but nothing.
Around the oil way on the bottom face that bolts against the crankcase there is a machined u shape recess the same as you'd put an o ring into (if it were round)

My question is should there be an o ring or something similar here or do I just need to use some gasket sealant? Have looked at the manuals and they don't show anything. If it doesn't need a seal what is the purpose of this recess?

Sorry if this is longwhinded and sorry I can't provide a pic.

Thanks in advance.

[M.V.]

G'day Alfow!

I recently swapped engines & oil tanks, I can't remember there being any o rings or anything similar in mine...

I did have an oil leak when I put the new engine in, but that was only because the oil tank bolts were loose.

Good luck!