Minimal oil to trigger the red light?

[Savago]

Dear friends

This last weekend I changed the oil in my sleepy I/S (after it was sitting for 1 year, poor girl...) and thought about using a 'cheap' oil for a shorter oil change interval (1000-2000 miles) to help 'flush' the engine.

I got a gallon of Rotella T4 (white jug, the mineral one) and performed the oil change. Damn! I had forgot how easy it is to do an oil change in a Valkyrie versus a ST1300 (all that tupperware to remove is a pain in the ass).

I drained the old oil and filled in with the new oil (2.7L to 2.9L), started the bike and let it run for 1 minute and after a little while (a few minutes), I completed to the correct mark in oil dip stick.

Something occurred to me though: even with way less than 3.7L, the engine run without the red light for low oil pressure.

I have the impression that this flat-6 engines are really easy on oil and don't require much to continue running.

Which leads to the question: what would be approximately the minimal amount of oil that would trigger the low oil pressure red light in a valkyrie? Anyone has an idea?

[Bighead]

Dont know but I keep 4 Quarts in mine.....dont know what that is in liters and dont want to calculate it.
Your mileage may vary.

[Savago]

@Bighead: 2.8L equals 3 quarts.
 

[Bighead]

Learn something everyday....even if I will never use it 

[The emperor has no clothes]

I don't know the answer. But, I can relate this story to you. When I bought my Standard, I took off down the road to test it out. Ran fine, no light. Next day I change the oil. Only one quart came out. I was worried that I had done damage to it. But 50k later it's still running strong. So, I guess it takes less than a quart.

[Jims99]

As long as the oil covers the pick up, it will have oil pressure. Light won’t come on unless it starts sucking air, oil thins out to much, or problem in engine. Low oil will heat up and break down much faster. These engines are well designed, don’t really need much to run but keep topped of do it will last for 300k.

[Jess from VA]

When I change the oil, with the filter off and oil drained, I always bump the starter a couple times to blow out any additional crud that I can (doing this and leaning the hot bike all the way right while draining, I always get in the whole gallon vs the 3.9qts mentioned in the manual).  I try not to let the engine start, but it has started, and guess what, no oil light ever came on, even empty.  However, I never let it run for more than a second or three.

Always using good synthetic, I could probably motor around with no oil at all for a mile or more with no problem.  Not that I would ever do that to find out.

[98valk]

3.7L or 3.9 US Qts. 

1 gal/4 qts = 3.7854 L

3.9 US qts = 3.6907 L

[Paladin528]

The light is triggered by oil pressure.  As long as the oil pump is able to pick up oil the light will remain out.  Still not a good idea to run with low qty.

[Savago]

@meathead: Quite interesting feedback, and really crazy that with just 1 quart it won't crap out.
 

@all:
Indeed, no reason at all to let the engine running on low oil (as oil is cheap and an engine rebuild is quite expensive).

I'm assuming that even if the low oil pressure light wouldn't come out, probably the engine temperature (both oil and coolant) would be *much* higher than normal? I would expect at least the oil temperature to be higher.

Just wondering if there is a way to identify such scenario *while* the engine is in operation (i.e. riding)... Maybe an Autometer oil pressure gauge would do the trick?

I guess in the end, there is a reason why there is an oil dip stick (even though this bikes never lower the oil and most valkyrie riders never check the oil level).
 

This is a point where I wished that mother honda have used those sight glasses that allows to check the oil level in the engine: