Martin H. Eastburn wrote:
I don't know - think of it this way...

a small drip from the bottom point will drip out the micro carbon chunks
that grind away on things. This was likely the early way before some
detergent oils were developed to keep them floating around and out of the
oil sump pump.

I have my air tank that way - sizzle a little and the water is let out.
It acts like a leak - but it is a useful leak.

I think this is debatable. The oil at the very bottom of the sump is
likely stagnant anyway, so contaminants there probably don't circulate
through the engine much. And if your bike leaks oil, the chances are
that at some point the oil level will get low. If it gets too low,
that'll wear out your engine a lot quicker than a few contaminants.
Lastly, it creates a mess everywhere, so I'm doubtful that Harley
Davidson created the leaks on purpose.

It's also my understanding that you shouldn't put modern oils with high
detergent and dispersant concentrations into older engines which only
have a gauze oil strainer. Those additives are meant to dissolve all the
contaminants and keep them in circulation until they can be removed by
one of those cartridge-type paper filters. If you don't have one of
those, anything small just stays in circulation and causes wear. Better
just to let it fall to the bottom of the sump.

Best wishes,

Chris