When building my race engine, I gave some thought to the route of the air/fuel/oil mix from carb to cylinder head. The front cylinder is a nice straight run, but the rear required the air/fuel/oil to go round a 90 degree bend. I assumed this was why there was double the lube pools and two oilways vs only one at the front, as it affects the speed of the gases and what oil they 'dump' on the journey. I filled the pools on my race bike and with 'scheduled maintenance' as Chester Roy says, I've never had a problem with crank mains failing.
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