Vintage BMW Motorcycle Owners

You are doing the right thing, LOL sometimes we make mistakes, I have had things "repaired" only to have to repair them again because of something I put in wrong. Carbs are my biggest thing for doing this. St.

Several other new owners of BMW airheads have had concerns about low oil pressure at idle only to realize that the red light is actually the alternator charging light.

I hope you read the part where I used 2 different gauges to confirm that the pressure is low? I am not relying upon the idiot lamp in the dash to determine the issue. I am using an EME charging system, so my gen lamp does not come on at idle anymore.

P-Funk wrote: ↑

Sat Nov 20, 2021 3:34 pm

I hope you read the part where I used 2 different gauges to confirm that the pressure is low? I am not relying upon the idiot lamp in the dash to determine the issue. I am using an EME charging system, so my gen lamp does not come on at idle anymore.

Yes I did read that you have used two different pressure gauges that indicate 15 psi at hot idle and two different pressure switches that occasionally trigger the dash light at idle. With the switches operating at approximately 7 psi it seemed a possibility that a new owner might have confused the two lights.
I apologize if I offended you.
Brett

Not offended actually.
My disassembly to the oil pump has begun, I have managed to remove the air filter box, battery and tray, along with having to disconnect alot of wiring that was sitting in the seat tray.

What are your rpm’s at idle? It’s a good sign if you have oil coming out of the rockers when just cranking over. I would also check your oil cooler lines to see if they are warm right away after start up. Please post what you find.
Doug

RPM at idle does not mean a thing. Once the bike has run a few seconds after starting the oil pressure light should go out completely and stay off. The light is not supposed to come on at any time the bike is running as long as things are working the way they should be working. This is not like the charging system light which will come on at low idle.

A oil pressure light that comes on when the bike is running means SOMETHING is wrong. it may just be the sender switch or a bulb issue but it needs to be investigated soon. The owner of this bike is doing just that, which is good.

Hopefully he will fill us in on what he has found causing his problem. I wish him good luck and good hunting. St.

I have moved the motorcycle from the cold garage to the warm(er) basement.
I will be doing work on this until the oil pump has been inspected or I know more.
As of right now, I have the drive shaft bolts out, but I need to lift the frame to pull the rear wheel, also to remove the mufflers to get the wheel axle out.

I'll be back to report more -

many thanks, folks!

Sorry we couldn't have done it in my garage, but, you are making progress. Good luck, and keep us updated. St.

So, I'll spare you all of the usual tear down joy, and just say that I have reached the oil pump tonight.
Nothing abnormal to be found along the way, this is the second time I have ever done it and it went twice as quick as previous. I strapped the nose of the crankshaft with a come along, to prevent it from moving forward. I do have the timing cover off, the front end is exposed, so as to get at the over pressure valve found near the chain.

I do have a question for the group - on the original 1982 oil pump's outer rotor, the surface is smooth, fully round. On the replacement outer rotor that I bought, there is a notch cut across the face/surface, as if to engage a woodruff key if it were in the bore. I know that the inner rotors from previous models have this keyway, but I am referring to the outer rotor, outer edge. There is no male counterpart for this rotor to engage on, the bore is fully smooth. Perhaps it is used to move along debris, I don't know.

EME sells the notched version, as seen in this link- have a look - https://www.euromotoelectrics.com/produ ... ter293.htm

Would that notch make a pressure difference when used? I think not, but I have to ask. It would seem to me that both ends of the notch are blocked from allowing oil to pass.

The O ring under the cover plate seemed to be in tact, in its groove - just compressed in a few areas, but not pinched.
Honestly, the only other thing that I found was that the cover plate bolts could have been tighter, they were snug but not forcefully on.

I took pictures with the intent on putting them here, but the upload format did not allow my files to be placed here.

i'll read responses tomorrow.

thanks

Had the experience of the oil pressure relief valve failing/coming apart causing oil light to come on at idle. Its a rare failure but it happens.

I too inspected all other systems until this ended up being the culprit.

May/may not applicable in your case. Good luck