Priming the bottom end

[berger]

years ago in the 80's i took mine for a walk in 4th gear ever since then i have well lubed the parts and fired it up noting it takes only a few seconds for returning oil. the only times i have known my bike not to return oil through the return pipe is when i put the pipes on wrong and when my mate owned it in the 70's and poured stp oil treatment into the tank and it took well over a minute to start returning while we panicked

[groily]

I was pretty much the same Bergs back then, but I nowadays do what you and Rex and others do.
(Worth reminding oneself that returning oil doesn't mean much though if you've chucked half a pint down the engine during assembly, just proves the scavenge side works - unless you have a loooong hard look at the return.)

If you were really religious about pushing things in top with the plugs out, or kicking away for ages at risk to kickstart teeth etc, you'd be maybe doing it every oil change, not just after a rebuild, 'cos by the time you've drained tank, sump, oil pipes, filters etc - and probably left things open to drip away while you have a cup of, a Black &T, a smoke  , or a break for some recreational with the beloved (yeah, right), there's norrawholelot in there priming things, just residual 'dirty' on journals, trapped in troughs etc.

[berger]

i drain the sump squirt into rocker spindles make sure delivery to engine is full fire it up and watch it speedily flow up the clear pipe to the rockers and tank .