That is the question! And I imagine it's been discussed many times. This is further to recent discussions (on topics started by me and by Elevensies) about wet-sumping and oil taps.
I became aware of the extent of my wet-sumping when I noticed oil under the bike, and a dramatic drop in the level of the oil in the tank, after the bike had been stood for a few weeks. At least some of the leak seemed to be coming via the gearchange lever. That drop in oil level in the tank suggested to me that the wet-sumping problem was on the feed side. So anyway I needed to do something. Seeking advice on this forum is usually the first thing I do!
Emptying the sump every time doesn't seem a very attractive proposition.
Having a tap is obviously fraught with risk - forget once to turn it on, and there would be a disaster. I understand that, and do feel a bit nervous about it, obviously.
So it would be ideal to address the source of the problem, which, I assume, is the non-return valve (feed side)? I believe it is a spring and ball. Attached is a photo of Rupert Ratio, vol 1, p.30. I THINK my bike (1965 B40F) is "end fed crank", ie Illus 5.2 on the photo. Anyway, whether it is "end-fed crank" or "timing side bush" (Illus 5.1), either way , the non-return valve ("A" on the illustration) appears to be in the depths of the crankcase, so not exactly easy to get at. For a novice like me, with a garden shed (about, say, 13 ft x 7 ft), small bench, old vice, box of hand tools, and very little know-how, to get at that non-return valve seems a bit unrealistic. Would you agree? I guess it must be a pretty big job, or why would anyone fit a tap?
I would love to think I could sort out the non-return valve, but it seems that at this stage the tap is the way to go. Do you agree? Phil.