Oil, oil pumps and primary chains

[Bryanj]

The long drain fully synthetic oil for trucks is now supposed to stay in for 180,000 Km YES YOU DID READ THAT RIGHT!!! before needing changing, which is good when its

[ST1100]

I ran the factory filled oil (whatever that was) for like 1000km/600miles in both bikes as well as in them cars, like as a 'brake-in oil' (very old fashioned I know  , but it gave me some confidence), to then change filter and oil to my 'preferred' full-synth weight/type.
I did notice that all engines required a higher milage to finally 'free up', like 20Tkm/12,5Kmiles at least, while never showed any mentionable rate of oil consumption either, even after well exceeding the 100Tkm/60Kmiles (bike) or close to 300Tkm/187Kmiles (car, petrol engine); which would confirm lower friction, thus lower wear of parts due use of full-synth.
On cars I use 5W40, on the bike the 5W60 on which I frequently receive objections about using a higher grade then rated by the manufacturer (except from my well trusted mech, who's fully confident on that oil  ), but I think that since a motorcycle engine is driven way harder, I like to have some reserves; an issue maybe even more critical on them air-cooled, thus partially hotter running SOHC engines.
With the 5W60 I can further maintain a 'touring friendly' interval of 12Tkm/7,5Kmiles, instead of the 6Tkm/3,7Kmiles suggested by the manufacturer, due which I would not be able to make my runs without being grounded for 'overhaul' somewhere along, which also helps to make the of course higher price of this 'liquid-gold' more bearable as well 
I would however not extend the interval beyond this, over factors like shear and chemical contamination...

As with your Audi, also the guts of my engines are just 'sparkling clean', no sludge, no deposits, no sooth, just spotless, amazing me newly every time I wrench on them...

However have I been told that its not adviseable to change the oil type once an engine has been ran with a particular type (dino, semi, full) over a longer period, as such could lead to soften/loosing deposits that have aided sealing, leading to a previously not occurring oil consumption.
I also don't know how, or how much of it applies to the sinthered connection rod bearings?
Further will the plates of wet clutches have saturated with the used oil, which then might not work properly with the now 'new' oil there.
I'd actually experienced such once, as my mech was not avail once and they'd incidentally filled a 'standard' oil into my engine, causing the clutch to not fully disengaging, plus not properly engaging either... a look at the view glass gave it away then...

[K2-K6]

I know this is somewhere adrift of the original post but has some very interesting points that are relevant.

The HGV stuff certainly puts us into perspective as regards longevity. As I understand it when you change the oil frequently what you are really doing is throwing away the contamination as opposed to the oil breaking down from it's normal operating function. This is why you should limit on choke running to as small as possible time to prevent just throwing petrol/combustion waste into the oil on these old bikes.

For years we've had oil spec for example rear axle of a car that has no polutants from combustion and no requirement to change them for the life of the vehicle.

I understand for new engines now one of the issues of running in is to get the bores and rings to seal properly and modern synthetics can prevent some of this process happening. If you accept that the rings when squeezed into the bores are not perfectly matched to the bore shape then, it's the action of the bore hone sharp edges that effectively "file" the rings into a best possible match and hence most effective sealing. Once the minute sharp edges are smoothed from the honing process then very little further improvement will happen, this is the reason for some very specific oil requirements for initial running and you also need to use the engine throughout a wider range than past convention would suggest. I believe some car turbo desiels suffer from high oil use later in their mileage if this is not effectively completed. In effect you initially at least have a conflict of promoting some ideal wear characteristics while still protecting the other bearings etc from any wear. This is also why you need an oil change so soon to throw out the tiny particals you've worn off the bores/rings.

[Bryanj]

I must admit most new hGV have a centrifugal filter as well as paper element, as to the running in bit Kawasaki had a problem with the first 1,000cc fours in that a lot of UK riders were running them in to slowly and glazing the bores and they were being re-bored under warantee plus owners told to go out and use them properly!!

[K2-K6]

Here's an interesting piece of information, from a Honda shop manual for 1978 covering american models K8 and F3 750cc SOHC (UK models K7 and F2).

It quotes for "oil specification"

HONDA 4 STROKE OIL or an equivalent.
API service classification; SE
Viscosity; General all temperatures SEA 10W-40

Alternate

above 15 C  SAE 30
0 C - 15 C SAE 20 or SAE 20W
below 0 C SAE 10W

Nothing is stated about car/motorcycle oil.

I'd guess at anything in the 0W-to-5W range was not generally available off the shelf when that was written.

Also it states from new/empty fill 3.5ltrs and from oil change 2.5ltrs including filter/sump/oil-tank emptied.