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Life of Hi........................Vo

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Bryanj:
Higher revs and more snatching would be my thoughts

K2-K6:
In comparison to use in different systems there's some interesting details that come up, which I feel impact how it runs in these engines.

Primarily it appears that the oil fails to sufficiently protect the chain's load bearing surfaces, but notice how it doesn't impact the drive teeth on crankshaft and layshaft.
They appear to make grey oil "slurry" that's consistent with the metal product left on an oil stone when you grind/finish working tools during sharpening. 
You get this ferrous oil "peanut butter" stuck to the sump  plug/magnet on engines as collected evidence some times. As most of the other engine parts are usually still in place (on well lubricated examples) although it's small assumption,  reasonable to think it's primarily coming from the chain.
If the oil film fails,   it's most likely causes are;- not meeting a standard suitable to prevent wear or condition of oil that stops it holding it's designed qualities, inability to replenish at acceptable rate to prevent localized breach of film, and associated with that,  going over heat to cause breakdown of film when exceeding operating temperature range.

Laverda Dave:
Back in the day (70's/80's) bike testers would always mention 'backlash' on Jap bikes. Is this backlash a result of using HY-VO chains for primary transmission and would backlash be an issue if the primary drive was by gears and not chain? Would backlash also increase as the primary chain wears? Or is backlash a result of designed in freeplay on the gear shafts to enable gears to engage properly?

K2-K6:
There's a specific part of the design that may have influenced that scenario.

The Japanese gearboxes being generally oriented such that the drive comes out of the clutch through gearbox main shaft,  then crossed to the secondary gear shaft to go out of the box from that shaft. This involves two sets of gear dog backlash, one on each shaft for all ratios.

Whereas some of the British boxes favour the output on the same, principal, shaft as the clutch.  This gives intermediate ratios going to the secondary "lay" shaft and then back to the main shaft to get out.  But the top gear would be direct from clutch to output sprocket on the same shaft. Most car gearbox are like this too. In effect no backlash at all for top gear, additionally it has no paired gear losses for top gear either, and so has a frictional advantage. 

Steady cruising with throttle on/off would show more shunting on the first type.

K2-K6:
To add, most (well all really) road vehicles have built in "lash" between engine and gearbox as they are quenching the peaks of crankshaft speed oscillations to prevent them hammering the onward drive components. Hugely helps to take out noise and vibrations rather than amplifying them.

Generally it'll be at the clutch, with things like current diesel engines using dual mass flywheel in which one of the functions is to allow the crankshaft something like 120 degrees rotation freedom ( contained by springs) to filter out the chunky bits of torque at low rpm and make them sound more sophisticated than crankshaft pulses would allow. 

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