Why don't wetheads have an oil pressure warning light?

[Hedghog]

First time poster.

 

Bought a 2018 R1200RT new...have just been riding it alot and haven't had a reason to hit the forums until now.

 

I recently did an oil change and didn't have the oil filter on quite tight enough so it developed a drip within the first few minutes.

 

I gave the throttle a few gentle tugs during the process and noticed the bike didn't seem to like it...kind of a de-tuned sound from the exhaust.

 

There were no abnormal warning lights on the dash before shutting it down which got me searching for an oil pressure warning light in the owners manual and to my surprise there isn't one.

 

This seemed extremely strange to me since this is exactly the type of scenario where an oil pressure warning light is commonly used.

 

This got me thinking a little more and now I am wondering if the motorcycle simply de-tunes the engine as oil pressure decreases to the point were it shuts down to save the engine.

 

It would be foolish for BMW to do away with an oil pressure warning light unless there was something in the engines control system to save the engine from destroying itself in the advent of low oil pressure.

 

Any feedback concerning this matter would be appreciated.

[TSConver]

There is no oil pressure sensor anywhere on the bike so it cannot detune if the pressure is low.

[lkraus]

How far did you ride before noticing this "de-tuning"?

 

How far did the oil level drop?

 

There is an oil level  warning, did that appear? 

[Skywagon]

also using the whizzy wheel you can check your oil....not the level, but ok or not ok.

[TSConver]

21 minutes ago, lkraus said:

How far did you ride before noticing this "de-tuning"?

 

How far did the oil level drop?

 

There is an oil level  warning, did that appear? 

 

It only works once the motor is completely warmed up and in gear and upright.  Could loose a lot of oil before that happened.

[TSConver]

11 minutes ago, Skywagon said:

also using the whizzy wheel you can check your oil....not the level, but ok or not ok.

How do you check it with the whizzy wheel?  Are you referring the level indicator?  Only works when completely warmed up.  No oil pressure gauge on any of the liquid cooled bikes.  Have searched the parts fiche to find one and there is not one listed not even a simple pressure switch to warn of low pressure.

[Skywagon]

TS.. will post when I get home tonight. Don’t remember off the top of my head but I check it when riding… again it just says ok, does not give level

[TSConver]

15 minutes ago, Skywagon said:

TS.. will post when I get home tonight. Don’t remember off the top of my head but I check it when riding… again it just says ok, does not give level

It is just a minimum level, again only works when it fully warmed up.

[Hedghog]

10 hours ago, TSConver said:

There is no oil pressure sensor anywhere on the bike so it cannot detune if the pressure is low.

Then I would say thats a design flaw

[Hedghog]

10 hours ago, lkraus said:

How far did you ride before noticing this "de-tuning"?

 

How far did the oil level drop?

 

There is an oil level  warning, did that appear? 

Didn't ride anywhere...noticed a bit of oil on the shop floor...maybe 2 tablespoons....shut it down soon after.  No abnormal warning lights on the screen.

[lkraus]

That small amount of oil loss would not have affected the way the engine runs, or trip a warning light for low oil level (or loss of pressure, if it had a pressure sensor).

[Hedghog]

54 minutes ago, lkraus said:

That small amount of oil loss would not have affected the way the engine runs, or trip a warning light for low oil level (or loss of pressure, if it had a pressure sensor).

The engine was still cold so what seemed like a de-tuned throttle response may not have been caused by a reduction in oil pressure...but its difficult to say.  Lower than normal oil pressures can reduce engine performance.  I agree the low oil level warning would have not tripped.

 

In any event, I am pestering BMW via email to see if there is a reason they got rid of the oil pressure warning light when the wethead was introduced.

[wbw6cos]

Loss of pressure usually indicates no oil.   The warning will come on when the oil level gets too low, which comes on just below half way in the sight glass; it will indicate add oil.

 

You may want to re-trace what you did to confirm nothing out of the ordinary was disturbed.   Go ride it and have fun!

[JCtx]

I can't believe we wouldn't get a CEL if oil pressure is low enough. Maybe there's no specific low oil pressure idiot light, but there has to be a sensor in there that would trigger a CEL, no? Even super old cars and bikes had protection against that. You could have low oil pressure with correct level (like a bad oil pump), so the former typically has priority. Some vehicles don't report low oil level, but all report low oil pressure. I'd be extremely surprised if our bikes wouldn't do that, but it'd be nice to know for a fact. A good way to know would be by studying all inputs into the ECU. Or all sensors present on the bike.

[dirtrider]

8 hours ago, JCtx said:

I can't believe we wouldn't get a CEL if oil pressure is low enough. Maybe there's no specific low oil pressure idiot light, but there has to be a sensor in there that would trigger a CEL, no? Even super old cars and bikes had protection against that. You could have low oil pressure with correct level (like a bad oil pump), so the former typically has priority. Some vehicles don't report low oil level, but all report low oil pressure. I'd be extremely surprised if our bikes wouldn't do that, but it'd be nice to know for a fact. A good way to know would be by studying all inputs into the ECU. Or all sensors present on the bike.

Morning JCtx

 

Not much in the engine electronics system could or would trigger a low oil pressure warning in time to save the engine. Once the engine seized you might get a non oil pressure related dash light. If you want to know the engine oil pressure then you need to have a switch or sensor in one of the oil pressure circuits. 

 

About the best low oil pressure warning (if ridden long enough) would be the cam chains getting noisy.  

 

If the low oil pressure was due to a low oil level then you would obviously get a low oil level warning if the engine is up to operating temperature & the other low oil warning criteria was met. 

 

Even on the older BMW motorcycles that had a low oil pressure warning, the Camhead low oil pressure warning  came on at just a tad over 2 psi, so at 3 psi it would not set a dash warning & at freeway speed  that isn't enough oil pressure to prevent engine damage at higher RPM's over a period of miles. 

 

For most riders for most situations the low oil level is probably a better warning than a low oil pressure warning that only comes on at under .15 bar. 

 

Your dash warnings should be in you riders manual, look around page 33 (give or take), if you see a stated warning or message that points to low oil PRESSURE then you have a low oil pressure warning (based on something). If your manual doesn't point out a low oil pressure warning then you don't have a low oil pressure warning system. 

 

I'm not sure if the 1250 even has an external oil pressure tap location. (I can't remember seeing one), if you can find an oil pressure threaded tap on your engine you could always add your own oil pressure gauge or light. 

[Boxflyer]

Here are some of my oil pressure monitoring tools. 
One each for CamHead, WetHead and ShiftHead engines. 
All are modified Cam Chain Tensioners. 

Brad

 

[JCtx]

On 6/25/2024 at 4:47 AM, dirtrider said:

If your manual doesn't point out a low oil pressure warning, then you don't have a low oil pressure warning system.

My 2020 does NOT have it then; only the low oil level warning mentioned. So probably same thing with all other 1250s. That's a little disturbing, but I'm not worried about it; never heard of a single case about that. But it's good to know it doesn't have that protection. Could be a worry WAY in the future, once the miles pass maybe 50K, but it won't happen under my ownership. In fact, not even close. Ha ha. Thanks for the help.