Leaky oil tank on plunger GF

[Greybeard]

I've been congratulating myself, (and blue Hylomar) that at 200 miles I currently have no oil leaks. However, (BTW; I'm enjoying these formatting buttons!) I am seeing a small spill of oil directly under the oil tank after a run. It doesn't seem to be coming from the breather pipe exit near the drive sprocket; the underside of the oil tank has oil on it. My first thought was that the tank may be leaking but then surely the oil would continue to leak. This spillage seems to stop after a while. When I changed the oil I did put a bit more in than last time but it's still three inches or so below the filler hole. I was wondering if oil was creeping across from one of the tank connections, (there is no direct drip from them) so last night I tightened and wiped all around them and this morning there was no oil around them but there was some over and on the breather outlet pipe. That pipe has a rubber tube pushed on that connects to the 'S' shaped pipe that goes to the sprocket area. I have not Jubed that tube; it's just pushed on; I figure there will never be any real pressure in that connection.
So, do I have a pinhole leak in my oil tank? The tank was not very rusty before I stripped it and painted it but if it is leaking that will be a ball-ache: I may just have to live with the leak until the next major refurb. Got rag in pocket!

[KiwiGF]

I posted recently coincidentally about my s/a oil tank leaking, it was the seam at the bottom, only a pressure test showed it up when the tank was on the bench, it leaked quite a lot on the bike i guess only when hot. But was little more than a pin hole, not rust caused but maybe a failure in the original jointing method when the 2 halves were put together.

I plastered the edge of the seam with soft solder and one day will get around to fixing it properly !

[Greybeard]

Interesting KiwiGF,

To solder the seam you must have achieved real cleanliness! I was thinking along the lines of using a liner such as POR-15, that I had to use to seal rust in my fuel tank. I should be able to do that without stripping the paint from the oil tank.