ET: Engine (Twin) Air bubbles in Oil Return

ericg

ericg

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Mike 40M said:
If empty, you can go 10 miles before it seizes.
A slight drawback with an anti wet sumping valve.
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I use an anti sumping valve in My Norvin for about 30 000 miles with no problem so far. I arranged a piece of clear pipe too see the oil flow as a security check though.
Same thing with my Commando, 45 000 miles and never had any problem with the valve. An oil pressure gauge is fitted to check oil circulation as well as bottom end health.
 
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nigsey

nigsey

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davidd said:
I found that the earplugs allow you to hear more mechanical noises!

I think Simon said it well. The sump oil is whatever oil gets picked up by the flywheels and slung into the sump. If you did an oil change that would have slowed the oil at least until the sump filled up enough to get slung into the sump chamber. The scavenge side of the pump will push oil or air into the return pipe. It does not care. On the Egli, the bubbles would just advance through the clear plastic tubing if there was not much oil in the scavenge chamber.

It is the feed side of the pump that is more important at start-up. This is supplying the crank and cams. If that line is full you are likely to be fine.

David
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Many thanks David, I did drain the sump of about 1/4 pint so guess that could explain it. The good news is I went for a 70 mile ride today and of course I checked the oil return before I set off. Pleased to say that oil was flowing really well back into the tank and no visible bubbles.
 
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roger v

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timetraveller said:
Difficult to say too much but the Vincent oil pump always pushes air out with the oil, unless the sump is full, as the return side has a larger capacity than the feed side. Does it look different now from what it was like before?
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I am making an oil tank for my Norvin project , most of my other bikes have a breather from the engine into the tank and from there a discharge pipe to atmosphere . Should I follow this route with the twin engine
 
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